JP5051088B2 - Optical laminate, polarizing plate, and image display device - Google Patents

Description

The present invention relates to an optical laminate, a polarizing plate, and an image display device.

An image display surface of an image display device such as a cathode ray tube display (CRT), a liquid crystal display (LCD), a plasma display (PDP), an electroluminescence display (ELD), or a field emission display (FED) is irradiated from an external light source. It is required to reduce the reflection by light and to improve the visibility. On the other hand, it is generally practiced to reduce the reflection on the image display surface of the image display device and improve the visibility by using an optical laminate in which an antireflection layer is formed on the light transmissive substrate. It has been broken.

As an optical laminated body having an antireflection layer, a structure in which a low refractive index layer having a refractive index lower than that of a light-transmitting substrate is provided on the outermost surface has been known.
Such a low refractive index layer is scratched because it has a low refractive index to enhance the antireflection performance of the optical laminate, has excellent optical characteristics such as transparency, and is provided on the outermost surface. In addition to having high hardness for prevention and the like, it is required to have excellent contamination resistance.
As an optical laminated body in which such a low refractive index layer is formed on the outermost surface, for example, Patent Document 1 has a low refractive index layer containing hollow silica fine particles, a fluorine atom-containing polymer, and an antifouling agent. An optical laminate is disclosed.

However, in recent years, the display quality required for the image display device has become very high, and the optical characteristics required for the optical laminate have also become very high.
However, a conventional low refractive index layer containing hollow silica fine particles, a fluorine atom-containing polymer and an antifouling agent and imparted with antifouling performance has a problem that whitening occurs and optical characteristics are lowered. It was.
Therefore, the conventional optical layered body provided with such a low refractive index layer imparted with the antifouling performance cannot sufficiently meet the recent demand for high display quality of image display devices.
JP 2007-301970 A

In view of the above situation, the present invention has a low refractive index layer excellent in hardness, surface uniformity and low refractive index performance and excellent in optical characteristics without whitening, and has scratch resistance, antireflection performance and transparency. It is an object of the present invention to provide an optical laminate excellent in optical properties such as properties, a polarizing plate and an image display device using the optical laminate.

The present invention is an optical laminate having at least a low refractive index layer on a light transmissive substrate, the low refractive index layer comprising hollow silica fine particles, fluorine atom-free polyfunctional monomer, fluorine atom containing It is formed using the composition for low refractive index layers containing a polymer and an antifouling agent, and the antifouling agent is a silanol compound having a segment represented by the following general formula (1) It is an optical laminated body characterized by these.

一般式（１）中、ｎは、２〜１０の整数であり、ｍは、２〜３００の整数であり、Ｒは、下記一般式（２）で表される構造である。

In general formula (1), n is an integer of 2 to 10, m is an integer of 2 to 300, and R is a structure represented by the following general formula (2).

一般式（２）中、ｘ、ｙ、ｚは、０〜２０の整数を表す。

In general formula (2), x, y, z represents an integer of 0-20.

In the optical laminate of the present invention, the fluorine atom-free polyfunctional monomer is pentaerythritol tri (meth) acrylate, dipentaerythritol hexa (meth) acrylate, pentaerythritol (meth) tetraacrylate, dipentaerythritol penta (meth). It is preferably at least one selected from the group consisting of acrylate, trimethylolpropane tri (meth) acrylate, dipentaerythritol tetra (meth) acrylate, and isocyanuric acid-modified (meth) triacrylate.
The refractive index of the low refractive index layer is preferably less than 1.45.
The optical layered body of the present invention preferably has a hard coat layer or an antiglare layer between the light transmissive substrate and the low refractive index layer.

This invention is also a polarizing plate provided with a polarizing element, Comprising: The said polarizing plate is a polarizing plate characterized by providing the above-mentioned optical laminated body on the polarizing element surface.
The present invention is also an image display device including the above-described optical laminate or the above-described polarizing plate on the outermost surface.
The present invention is described in detail below.

Low refractive index layer The present invention is an optical laminate having at least a low refractive index layer on a light-transmitting substrate.
The said low refractive index layer means a thing with a refractive index lower than the refractive index of structures other than low refractive index layers, such as a light-transmitting base material which comprises the optical laminated body of this invention.
In the optical layered body of the present invention, the low refractive index layer is formed using a composition for a low refractive index layer containing hollow silica fine particles, a fluorine atom-free polyfunctional monomer, a fluorine atom-containing polymer and an antifouling agent. It has been done.

The hollow silica fine particles serve to lower the refractive index while maintaining the layer strength of the low refractive index layer. In the present specification, “hollow silica fine particles” refers to a structure in which gas is filled and / or a porous structure containing a gas, and the gas occupancy rate compared to the original refractive index of silica fine particles. Means a silica fine particle whose refractive index decreases in inverse proportion to
Further, in the present invention, the nanoporous structure is formed on at least a part of the inside and / or the surface depending on the form, structure, aggregation state, and dispersion state of the coating film using the above composition for low refractive index layer. Also included are silica particulates capable of forming a structure.

Specific examples of the hollow silica fine particles are not particularly limited, and for example, silica fine particles prepared using a technique disclosed in Japanese Patent Application Laid-Open No. 2001-233611 are preferable. Since hollow silica fine particles are easy to manufacture and have high hardness themselves, when mixed with an organic binder to form a low refractive index layer, the layer strength is improved and the refractive index is adjusted to be low. It becomes possible to do.

In addition to the above-mentioned silica fine particles, the silica fine particles capable of forming a nanoporous structure inside and / or at least part of the surface of the coating film are manufactured and used for the purpose of increasing the specific surface area. Columns, adsorbents that adsorb various chemicals on the porous portion of the surface, porous fine particles used for catalyst fixation, or dispersions or aggregates of hollow fine particles intended to be incorporated into heat insulating materials or low dielectric materials A collection is mentioned. As a specific example, aggregates of porous silica fine particles and silica fine particles manufactured by Nissan Chemical Industries, Ltd. were linked in a chain form from the product names Nippon and Nippon manufactured by Nippon Silica Kogyo Co., Ltd. as commercial products. Examples thereof include colloidal silica UP series (trade name) having a structure. Among these, those within the preferred particle diameter range of the present invention can be used.

The average particle size of the hollow silica fine particles is preferably 5 to 300 nm. When the average particle diameter of the hollow silica fine particles is within this range, excellent transparency can be imparted to the low refractive index layer. A more preferred lower limit is 8 nm, a more preferred upper limit is 100 nm, a still more preferred lower limit is 10 nm, and a still more preferred upper limit is 80 nm.

In the composition for a low refractive index layer, the content of the hollow silica fine particles is not particularly limited, but is an organic binder component (solid content) 100 such as a fluorine atom-free polyfunctional monomer and a fluorine atom-containing polymer described later. It is preferable that it is 200 mass parts or less with respect to a mass part. If it exceeds 200 parts by mass, the low refractive index layer to be formed cannot be made sufficiently low in refractive index, but the strength may be insufficient. A more preferred lower limit is 10 parts by mass, and a more preferred upper limit is 165 parts by mass.

In the optical layered body of the present invention, the antifouling agent is a silanol compound having a segment represented by the following general formula (1).

一般式（１）中、ｎは、２〜１０の整数であり、ｍは、２〜３００の整数であり、Ｒは、下記一般式（２）で表される構造である。

In general formula (1), n is an integer of 2 to 10, m is an integer of 2 to 300, and R is a structure represented by the following general formula (2).

一般式（２）中、ｘ、ｙ、ｚは、０〜２０の整数を表す。

In general formula (2), x, y, z represents an integer of 0-20.

The composition for low refractive index layer contains a silanol compound having a segment represented by the general formula (1) as an antifouling agent, so that the low refractive index layer to be formed has a uniform surface. It has excellent low refractive index performance and sufficient hardness, is excellent in antifouling resistance, and has excellent optical properties that do not cause whitening. This is presumed to be due to the following reasons.
That is, conventionally, in the low refractive index layer provided with antifouling properties and low refractive index containing hollow silica fine particles, a fluorine atom-containing polymer and an antifouling agent, the antifouling agent is a silicone-based antifouling agent. The agent was used. This is because the coating liquid containing the antifouling agent and the like with respect to an object on which a low refractive index layer such as a hard coat layer is formed is excellent in repelling prevention performance.
However, such a silicone-based antifouling agent has a high affinity for hollow silica fine particles, and the amount taken into the hollow silica fine particles in the coating solution is increased, so that the antifouling sufficient for the low refractive index layer is sufficient. In order to impart the properties, it was necessary to increase the amount added to the coating solution. On the other hand, the silicone antifouling agent is poorly compatible with the fluorine atom-containing polymer, and in the low refractive index layer provided with the antifouling property and low refractive index, it contains a large amount of fluorine atom-containing polymer. It is presumed that the added antifouling agent causes phase separation in the coating solution and the coating film, resulting in whitening and inferior optical properties such as transparency.
On the other hand, the silanol compound having the segment represented by the general formula (1) hardly causes phase separation from the fluorine atom-containing polymer, and the low refractive index layer contains such a silanol compound as an antifouling agent. The low refractive index layer formed by using the composition for use has a uniform surface and sufficient antifouling property, and is excellent in optical properties with little whitening. This is because the polymerizable unsaturated double bond of the side chain having a polymerizable unsaturated double bond in the general formula (1) corresponds to an object to be formed with a low refractive index layer such as a hard coat layer. While contributing to prevention of repelling, the alkyl part or polyether part represented by R of the side chain improves compatibility with the fluorine atom-containing polymer and contributes to prevention of whitening of the formed low refractive index layer. It is thought that it is from.

In the segment represented by the general formula (1), the number (n) of units to which the side chain having a polymerizable unsaturated double bond is bonded is 2-10. If it is less than 2, the composition for low refractive index layer will be repelled against the object to be coated, and a low refractive index layer having a uniform surface cannot be obtained. In addition, since the acrylate group in the antifouling agent is reduced, the reactivity with the fluorine atom-free polyfunctional monomer becomes poor, and when contaminants adhere to the low refractive index layer, the wiping performance deteriorates if wiped off repeatedly. There is a risk of doing. On the other hand, when the above (n) exceeds 10, the acrylate portion in the antifouling agent increases, so the compatibility with the fluorine atom-free polyfunctional monomer is improved and it is difficult to exist on the outermost surface of the low refractive index layer. As a result, the antifouling performance is significantly reduced. As for said (n), 2-6 is the most preferable range.

Moreover, the alkyl part or polyether part represented by R of the side chain which has the said polymerizable unsaturated double bond has a structure represented by the said General formula (2). In the said General formula (2), the repeating unit number (y) of an alkyl part and the repeating unit number (x, z) of a polyether part are 0-20. However, the number of repeating units (x), (y) and (z) of the alkyl part or the polyether part is not 0. That is, when (y) is 0, at least one of (x) and (z) is not 0, and when both (x) and (z) are 0, (y) is not 0.

A preferred range of the weight average molecular weight of the silanol compound is 500 to 50,000. If it is less than 500, the compatibility of the silanol-based compound with the fluorine atom-free polyfunctional monomer is relatively good, and sufficient antifouling performance may not be exhibited. On the other hand, if it exceeds 50,000, the compatibility of the silanol-based compound with the fluorine atom-containing polymer is remarkably lowered and separated, so that a good film may not be formed. Moreover, since it may whiten, it is not preferable. A more preferred lower limit is 5000, and a more preferred upper limit is 20,000.
In addition, the weight average molecular weight of the said silanol type compound can be calculated | required by polystyrene conversion by gel permeation chromatography (GPC). Tetrahydrofuran or chloroform can be used as the solvent for the GPC mobile phase. The measurement column may be used in combination with a commercially available column such as a column for tetrahydrofuran or a column for chloroform. Examples of the commercial product column include Shodex GPC KF-801, GPC KF-802, GPC KF-803, GPC KF-804, GPC KF-805 GPC-KF800D (all are trade names, manufactured by Showa Denko KK). Can be mentioned. As the detector, an RI (differential refractive index) detector and a UV detector may be used. Using such a solvent, column, and detector, the weight average molecular weight can be appropriately measured by a GPC system such as Shodex GPC-101 (manufactured by Showa Denko).

In the low refractive index layer composition, the content of the antifouling agent is preferably 0.05 to 10% by mass in 100% by mass of the solid content. If it is less than 0.05% by mass, sufficient antifouling performance may not be imparted to the low refractive index layer to be formed. If it exceeds 10% by mass, whitening occurs in the low refractive index layer to be formed. There is. A more preferable lower limit is 0.1% by mass, and a more preferable upper limit is 5% by mass.

The fluorine atom-free polyfunctional monomer is not particularly limited as long as it does not contain a fluorine atom in one molecule. For example, a functional group that cures by ionizing radiation in one molecule (hereinafter, ionizing radiation curable). And a monomer having a functional group that is cured by heat (hereinafter also referred to as a thermosetting group).

When the fluorine atom-free polyfunctional monomer has the ionizing radiation curable group, the fluorine atom-free polyfunctional monomer and It is possible to cure the coating film by proceeding with a large molecular weight reaction such as polymerization or cross-linking with other components.
Examples of the ionizing radiation curable group include those in which the reaction proceeds by a polymerization reaction such as photo radical polymerization, photo cation polymerization, or photo anion polymerization, or a reaction mode such as addition polymerization or condensation polymerization that proceeds through photodimerization. Etc. Among them, ethylenically unsaturated bond groups such as acrylic group, vinyl group and allyl group are directly photoradical polymerization reaction by irradiation of ionizing radiation such as ultraviolet ray and electron beam or indirectly by the action of initiator. It is preferable that it is relatively easy to handle including the photocuring step.

When the fluorine atom-free polyfunctional monomer has the thermosetting group, the fluorine atom-free polyfunctional monomer and / or the like can be obtained by heating a film formed using the low refractive index layer composition. The above coating film can be cured by advancing a large molecular weight reaction such as polymerization or crosslinking with the other components.

As said thermosetting group, an alkoxy group, a hydroxyl group, a carboxyl group, an amino group, an epoxy group etc. are mentioned, for example. Of these, a functional group capable of forming a hydrogen bond (hydrogen bonding group) is preferable. The hydrogen bonding group is preferable because it has excellent affinity with the hydroxyl group on the surface of the hollow silica fine particles, and improves the dispersibility of the hollow silica fine particles and the aggregate thereof in the composition for a low refractive index layer. .
The hydrogen bond-forming group is particularly preferably a hydroxyl group. The composition for low refractive index layer is excellent in storage stability and forms a covalent bond with a hydroxyl group present on the surface of the hollow silica fine particles by heat curing of the coating, and the hollow silica fine particles act as a cross-linking agent, and the film strength Can be further improved.

As the fluorine atom-free polyfunctional monomer, one having three or more reactive functional groups in one molecule is preferably used. Since the fluorine atom-free polyfunctional monomer has 3 or more reactive functional groups in one molecule, it can be easily applied in the coating film of the low refractive index layer composition by external stimulation such as irradiation with ionizing radiation or heating. It is possible to form a cross-linked bond and to efficiently cure the coating film, and the hardness of the resulting low refractive index layer is extremely excellent. Among these, a fluorine atom-free polyfunctional monomer having 3 or more (meth) acryl groups in one molecule is preferably used. In the present specification, the (meth) acryl group means an acryl group or a methacryl group.

Examples of the fluorine atom-free polyfunctional monomer having 3 or more (meth) acryl groups in one molecule include trimethylolpropane tri (meth) acrylate, pentaerythritol tri (meth) acrylate, and pentaerythritol tetra (meth). Examples include acrylate, dipentaerythritol hexa (meth) acrylate, dipentaerythritol tetra (meth) acrylate, and isocyanuric acid-modified tri (meth) acrylate. In addition, these (meth) acrylates may be partly modified in molecular skeleton, modified with ethylene oxide, propylene oxide, caprolactone, isocyanuric acid, alkyl, cyclic alkyl, aromatic, bisphenol, etc. Can also be used. These fluorine atom-free polyfunctional monomers may be used alone or in combination of two or more.
These fluorine atom-free polyfunctional monomers satisfy the refractive index range as described later and have excellent curing reactivity, and can improve the hardness of the resulting low refractive index layer.

The fluorine atom-free polyfunctional monomer preferably has a refractive index of 1.47 to 1.53. If it is less than 1.47, it is practically impossible to make it less than 1.47. If it exceeds 1.53, a low refractive index layer having a sufficiently low refractive index may not be obtained.

The fluorine atom-free polyfunctional monomer preferably has a weight average molecular weight of 250 to 1,000. If it is less than 250, the number of functional groups decreases, and the hardness of the resulting low refractive index layer may be reduced. If it exceeds 1000, the functional group equivalent (number of functional groups / molecular weight) is generally small, so that the crosslink density is low and a low refractive index layer having sufficient hardness may not be obtained.
In addition, the weight average molecular weight of the said fluorine atom-free polyfunctional monomer can be calculated | required by polystyrene conversion by gel permeation chromatography (GPC). Tetrahydrofuran or chloroform can be used as the solvent for the GPC mobile phase. The measurement column may be used in combination with a commercially available column such as a column for tetrahydrofuran or a column for chloroform. As said commercial item column, Shodex GPC KF-801, GPC-KF800D (all are a brand name, Showa Denko Co., Ltd. product) etc. can be mentioned, for example. As the detector, an RI (differential refractive index) detector and a UV detector may be used. Using such a solvent, column, and detector, the weight average molecular weight can be appropriately measured by a GPC system such as Shodex GPC-101 (manufactured by Showa Denko).

In the low refractive index layer composition, the content of the fluorine atom-free polyfunctional monomer is not particularly limited, but is preferably 1 to 95% by mass in 100% by mass of the solid content. If it is less than 1% by mass, the hardness of the low refractive index layer to be formed may be insufficient, and if it exceeds 95% by mass, the refractive index of the low refractive index layer to be formed may not be sufficiently reduced. . A more preferred lower limit is 10% by mass, and a more preferred upper limit is 80% by mass.

The said fluorine atom containing polymer is a substance which plays the role which reduces the refractive index of the low-refractive-index layer to form.
The fluorine atom-containing polymer is not particularly limited. For example, a part of acrylic or methacrylic acid and a fully fluorinated alkyl, alkenyl, aryl ester, fully or partially fluorinated vinyl ether, fully or partially fluorinated vinyl ester, completely Alternatively, partially fluorinated vinyl ketones and the like can be mentioned.

Examples of the fluorine atom-containing polymer include a monomer or a polymer of a monomer mixture containing at least one fluorine-containing (meth) acrylate compound of a polymerizable compound having an ionizing radiation curable group described above; fluorine-containing (meth) Fluorine atoms are not contained in the molecule such as at least one kind of acrylate compound and methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate ( Copolymer with (meth) acrylate compound; fluoroethylene, vinylidene fluoride, trifluoroethylene, chlorotrifluoroethylene, 3,3,3-trifluoropropylene, 1,1,2-trichloro-3,3,3- Trifluoropropylene, hexafluoropropyl Homopolymer of fluorine-containing monomers such as pyrene or copolymers thereof.

Moreover, the silicone containing vinylidene fluoride copolymer which made these copolymers contain a silicone component can also be used as said fluorine atom containing polymer.
Examples of silicone components in this case include (poly) dimethylsiloxane, (poly) diethylsiloxane, (poly) diphenylsiloxane, (poly) methylphenylsiloxane, alkyl-modified (poly) dimethylsiloxane, azo group-containing (poly) dimethylsiloxane, , Dimethyl silicone, phenylmethyl silicone, alkyl aralkyl modified silicone, fluorosilicone, polyether modified silicone, fatty acid ester modified silicone, methyl hydrogen silicone, silanol group containing silicone, alkoxy group containing silicone, phenol group containing silicone, methacryl modified silicone, Acrylic modified silicone, amino modified silicone, carboxylic acid modified silicone, carbinol modified silicone, epoxy modified silicone, mercapto modified silicone Corn, fluorine-modified silicones, polyether-modified silicone, and the like. Of these, those having a dimethylsiloxane structure are preferred.

In addition to the above, a fluorine-containing compound having at least one isocyanato group in the molecule, and a compound having at least one functional group in the molecule that reacts with an isocyanato group such as an amino group, a hydroxyl group, or a carboxyl group A compound obtained by reacting a fluorine-containing polyether polyol, a fluorine-containing alkyl polyol, a fluorine-containing polyester polyol, a fluorine-containing polyol such as a fluorine-containing ε-caprolactone-modified polyol, and a compound having an isocyanato group. A compound or the like can also be used as the fluorine atom-containing polymer.

Moreover, a commercial item can also be used as said fluorine atom containing polymer. Examples of commercially available fluorine atom-containing polymers that can be used in the optical layered body of the present invention include, for example, Opstar TU2181-6, Opstar TU2181-7, Opstar TU2202-7, Opster JN35, manufactured by Daikin Industries, Ltd. AR100 etc. are mentioned.

The fluorine atom-containing polymer preferably has a refractive index of 1.37 to 1.43. If it is less than 1.37, the solubility decreases, it becomes difficult to dissolve in a solvent, and handling may be difficult. If it exceeds 1.43, the refractive index of the low refractive index layer to be formed may not be reduced to a desired range.

The weight average molecular weight of the fluorine atom-containing polymer is preferably 10,000 to 200,000. If it is less than 10,000, the film formability of the composition for a low refractive index layer may be deteriorated. If it exceeds 200,000, phase separation is likely to occur in the organic binder, and the low refractive index layer to be formed is formed. Whitening may occur. A more preferred lower limit is 15000, and a more preferred upper limit is 150,000.
In addition, the weight average molecular weight of the said fluorine atom containing polymer can be calculated | required by polystyrene conversion by gel permeation chromatography (GPC) similarly to the silanol type compound mentioned above. As the measurement column, for tetrahydrofuran, for example, Shodex GPC KF-802, GPC KF-803, GPC KF-804, GPC KF-805, GPC KF-806, GPC-KF800D (all are trade names, Showa Denko).

In the low refractive index layer composition, the content of the fluorine atom-containing polymer is not particularly limited, but is preferably 10 to 95% by mass in 100% by mass of the solid content. If it is less than 10% by mass, the low refractive index layer to be formed may not be sufficiently reduced in refractive index. If it exceeds 95% by mass, the hardness of the low refractive index layer to be formed may be insufficient. A more preferable lower limit is 20% by mass, and a more preferable upper limit is 90% by mass.

In the optical layered body of the present invention, since the low refractive index layer is formed using the composition for a low refractive index layer having the above composition, the low refractive index layer is excellent in hardness and surface uniformity. At the same time, it has a sufficiently low refractive index, and further, it is excellent in optical characteristics without causing whitening.
Examples of the particularly preferred combination of the antifouling agent and the fluorine atom-containing polymer in the optical layered body of the present invention include the following combinations. In addition, an antifouling agent may mix 2 or more types in each combination.
(1) Antifouling agent: “TEGORad-2600” manufactured by Degussa
Fluorine atom-containing polymer: “AR110” manufactured by Daikin Chemical Industries
A combination containing
(2) Antifouling agent: “TEGORad-2700” manufactured by Degussa
Fluorine atom-containing polymer: “AR110” manufactured by Daikin Chemical Industries
A combination containing
(3) Antifouling agent: “TEGORad-2500” manufactured by Degussa
Fluorine atom-containing polymer: “AR110” manufactured by Daikin Chemical Industries
A combination containing
(4) Antifouling agent: “TEGORad-2200N” manufactured by Degussa
Fluorine atom-containing polymer: “AR110” manufactured by Daikin Chemical Industries
A combination containing
(5) Antifouling agent: “TEGORad-2500” manufactured by Degussa
Fluorine atom-containing polymer: JSR “JN35”
A combination containing
(6) Antifouling agent: “TEGORad-2600”, “TEGORAD-2200N” manufactured by Degussa
Fluorine atom-containing polymer: “AR110” manufactured by Daikin Chemical Industries
A combination containing

The combination of the antifouling agent and the fluorine atom-containing polymer provides a low refractive index layer having excellent hardness, surface uniformity and low refractive index performance and excellent optical characteristics without whitening. The optical laminate of the present invention is extremely excellent in optical properties such as scratch resistance, antireflection performance and transparency. Such an optical layered body of the present invention can sufficiently meet the high display quality required for recent image display devices.

The composition for a low refractive index layer may further contain a solvent.
The solvent is not particularly limited, and examples thereof include alcohols such as methanol, ethanol, propanol, isopropanol, n-butanol, s-butanol, t-butanol, benzyl alcohol, and PGME; acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, and heptanone. Ketones such as methyl acetate, ethyl acetate, propyl acetate, butyl acetate, methyl formate, ethyl formate, propyl formate, butyl formate, and PGMEA; aliphatic hydrocarbons such as hexane and cyclohexane; Halogenated hydrocarbons such as chloride, chloroform and carbon tetrachloride; aromatic hydrocarbons such as benzene, toluene and xylene; dimethylformamide, dimethylacetamide and n-methylpyrrolidone Amide; diethyl ether, dioxane, ethers such as tetrahydrofuran; ether alcohols such as 1-methoxy-2-propanol. Of these, methyl isobutyl ketone, methyl ethyl ketone, isopropyl alcohol (IPA), n-butanol, s-butanol, t-butanol, PGME, and PGMEA are preferable.

Moreover, the said composition for low refractive index layers may contain the other component as needed.
Examples of the other components include a photopolymerization initiator, a leveling agent, a crosslinking agent, a curing agent, a polymerization accelerator, a viscosity modifier, an antiglare agent, an antistatic agent, and resins other than those described above.

As the photopolymerization initiator, when the composition for a low refractive index layer contains a resin system having a radical polymerizable unsaturated group, acetophenones (for example, trade name Irgacure 184 (manufactured by Ciba Specialty Chemicals)) 1-hydroxy-cyclohexyl-phenyl-ketone), benzophenones, thioxanthones, benzoin, benzoin methyl ether, etc., which may be used alone or in combination of two or more. Also good.
When the low refractive index layer composition contains a resin system having a cationic polymerizable functional group, examples of the photopolymerization initiator include aromatic diazonium salts, aromatic sulfonium salts, aromatic iodonium salts, A metallocene compound, benzoin sulfonic acid ester, etc. are mentioned, These may be used independently and 2 or more types may be used together. Specifically, Irgacure 184, Irgacure 907, Irgacure 369, Irgacure 379, Irgacure 819, Irgacure 127, Irgacure 754, Irgacure 250, Irgacure 1800, Irgacure 1870R, Irgacure OXUO R01 , DAROCUR1173; SpeedcureMBB, SpeedcurePBZ, SpeedcureITX, SpeedcureCTX, SpeedcureEDB, Esacure ONE, Esacure KIP150, Esacure ONE , KAYACURE DMBI, and the like. Among these, Irgacure 369, Irgacure 127, Irgacure 907, Esacure ONE, Speedcure MBB, Speedcure PBZ, and KAYACURE DETX-S are preferable.
The addition amount of the photopolymerization initiator is 0.1 to 10 parts by mass with respect to 100 parts by mass of the organic binder component such as the fluorine atom-free polyfunctional monomer and fluorine atom-containing polymer. preferable.
Known leveling agents, crosslinking agents, curing agents, polymerization accelerators, viscosity modifiers, antiglare agents, antistatic agents, and other resins can be used.

The viscosity of the composition for a low refractive index layer is preferably in the range of 0.5 to 5 cps (25 ° C.), preferably 0.7 to 3 cps (25 ° C.) at which preferable coatability is obtained. An antireflection film excellent in visible light can be realized, a thin film with uniform coating uniformity can be formed, and a low refractive index layer having particularly excellent adhesion to an object to be coated can be formed. .

The method for preparing the composition for the low refractive index layer is not particularly limited. For example, the hollow silica fine particles, the fluorine atom-free polyfunctional monomer, the fluorine atom-containing polymer and the antifouling agent, and the solvent are necessary. It can be obtained by mixing components such as a photopolymerization initiator added accordingly. For the mixing, a known method such as a paint shaker or a bead mill can be used.

The low refractive index layer is a coating film formed by applying the composition for a low refractive index layer on a hard coat layer or an antiglare layer, which will be described later, and, if necessary, irradiation with ionizing radiation and / or heating. It can be formed by curing the coating film.
The method for applying the composition for the low refractive index layer is not particularly limited. For example, spin coating method, dip method, spray method, dye coating method, bar coating method, roll coater method, meniscus coater method, flexographic printing method. And various methods such as a screen printing method and a pea coater method.

In the optical layered body of the present invention, the low refractive index layer preferably has a refractive index of less than 1.450. When it is 1.450 or more, the antireflection performance of the optical laminate of the present invention becomes insufficient, and it may not be possible to cope with the high-level display quality of recent image display devices. More preferably, it is less than 1.425.

The film thickness (nm) d _A of the low refractive index layer is the following formula (I):
d _A = mλ / (4n _A ) (I)
(In the above formula,
n _A represents the refractive index of the low refractive index layer;
m represents a positive odd number, preferably 1;
λ is a wavelength, preferably a value in the range of 480 to 580 nm)
Those satisfying these conditions are preferred.

In the present invention, the low refractive index layer has the following formula (II):
_{120 <n A d A <145} (II)
It is preferable from the viewpoint of low reflectivity.

In the optical layered body of the present invention, since the low refractive index layer is formed using the composition for low refractive index layer having the above composition, the haze value of the low refractive index layer may be 1% or less. it can. If the haze value exceeds 1%, the light transmittance of the optical laminate of the present invention may be reduced, which may cause a reduction in display quality of the image display device. More preferably, it is 0.5% or less. In addition, in this specification, a haze value is a value calculated | required based on JISK7361.

The low refractive index layer preferably has a hardness according to a pencil hardness test according to JIS K5600-5-4 (1999) of H or higher, more preferably 2H or higher. Further, in the Taber test according to JIS K5600-5-4 (1999), the smaller the wear amount of the test piece before and after the test, the better. Further, for example, it is preferable that no scratch is generated in a scratch resistance test in which a friction load of 300 g / cm ² using # 0000 steel wool is used and the friction is repeated 10 times.

Light transmissive substrate The optical laminate of the present invention has a light transmissive substrate.
The light transmissive substrate preferably has smoothness and heat resistance and is excellent in mechanical strength. Specific examples of the material forming the light-transmitting substrate include, for example, polyester (polyethylene terephthalate, polyethylene naphthalate), cellulose triacetate, cellulose diacetate, cellulose acetate butyrate, polyester, polyamide, polyimide, polyethersulfone, poly Examples thereof include thermoplastic resins such as sulfone, polypropylene, polymethylpentene, polyvinyl chloride, polyvinyl acetal, polyether ketone, polymethyl methacrylate, polycarbonate, and polyurethane. Preferably, polyester (polyethylene terephthalate, polyethylene naphthalate) and cellulose triacetate are used.

The light-transmitting substrate preferably uses the thermoplastic resin as a flexible film-like material, but uses a plate of these thermoplastic resins depending on the usage mode in which curability is required. It is also possible, or a glass plate plate may be used.

In addition, examples of the light transmissive substrate include an amorphous olefin polymer (Cyclo-Olefin-Polymer: COP) film having an alicyclic structure. This is a base material in which a norbornene polymer, a monocyclic olefin polymer, a cyclic conjugated diene polymer, a vinyl alicyclic hydrocarbon polymer, or the like is used. ZEONEX, ZEONOR (norbornene resin), Sumitrite FS-1700 manufactured by Sumitomo Bakelite Co., Ltd., Arton (modified norbornene resin) manufactured by JSR Co., Ltd., Appel (cyclic olefin copolymer) manufactured by Mitsui Chemicals, Inc. Topas (cyclic olefin copolymer) manufactured by Ticona, Optretz OZ-1000 series (alicyclic acrylic resin) manufactured by Hitachi Chemical Co., Ltd., and the like.
Further, the FV series (low birefringence, low photoelastic modulus film) manufactured by Asahi Kasei Chemicals Corporation is also preferable as an alternative base material for triacetylcellulose.

The thickness of the light transmissive substrate is preferably 20 to 300 μm, more preferably the lower limit is 30 μm and the upper limit is 200 μm. When the light-transmitting substrate is a plate-like body, the thickness may exceed these thicknesses. The above light-transmitting substrate is formed with an anchor agent or primer in addition to a physical treatment such as corona discharge treatment and oxidation treatment in order to improve adhesiveness when forming a hard coat layer or the like to be described later. Application of the so-called paint may be performed in advance.

Hard coat layer, etc. The optical layered body of the present invention preferably has a hard coat layer or an antiglare layer between the light transmissive substrate and the low refractive index layer.
In the present specification, the “hard coat layer” refers to a layer having a hardness of 2H or more in a pencil hardness test defined by JIS K5600-5-4 (1999). The hardness is more preferably 3H or more. Moreover, as a film thickness (at the time of hardening) of the said hard-coat layer, it is 0.1-100 micrometers, Preferably it is 0.8-20 micrometers.

It does not specifically limit as said hard-coat layer, For example, what is formed with the composition for hard-coat layers containing resin and arbitrary components is mentioned.
As the resin, a transparent resin is preferably used. Specifically, an ionizing radiation curable resin, an ionizing radiation curable resin and a solvent-drying resin (during coating) are resins that are cured by ultraviolet rays or electron beams. The resin added to adjust the solid content is dried, and a mixture with a resin that forms a film), a thermosetting resin, or the like, preferably an ionizing radiation curable resin.

Specific examples of the ionizing radiation curable resin include those having an acrylate functional group, for example, a relatively low molecular weight polyester resin, polyether resin, acrylic resin, epoxy resin, urethane resin, alkyd resin, and spiroacetal resin. , Oligomers or prepolymers such as (meth) allylates of polyfunctional compounds such as polybutadiene resins, polythiol polyene resins, polyhydric alcohols, reactive diluents, and the like.

When the ionizing radiation curable resin is used as an ultraviolet curable resin, it is preferable to use a photopolymerization initiator.
Examples of the photopolymerization initiator include acetophenones, benzophenones, Michler benzoyl benzoate, α-amyloxime ester, tetramethylchuram monosulfide, and thioxanthones.
Further, it is preferable to use a mixture of photosensitizers, and specific examples thereof include n-butylamine, triethylamine, poly-n-butylphosphine and the like.

The solvent-drying resin used by mixing with the ionizing radiation curable resin mainly includes a thermoplastic resin, and the thermoplastic resin is not particularly limited, and conventionally known ones can be used.
By adding the solvent-drying resin, coating film defects on the coated surface can be effectively prevented. According to a preferred embodiment of the present invention, when the material of the light-transmitting substrate is a cellulose resin such as cellulose triacetate, preferred specific examples of the thermoplastic resin include cellulose resins such as nitrocellulose, acetylcellulose, and cellulose. Examples include acetate propionate and ethyl hydroxyethyl cellulose.

Examples of the thermosetting resin include phenol resin, urea resin, diallyl phthalate resin, melanin resin, guanamine resin, unsaturated polyester resin, polyurethane resin, epoxy resin, aminoalkyd resin, melamine-urea cocondensation resin, silicon resin. And polysiloxane resin.
When using the said thermosetting resin, as needed, hardening agents, such as a crosslinking agent and a polymerization initiator, a polymerization accelerator, a solvent, a viscosity modifier, etc. can be further added and used.

The hard coat layer is formed by applying the composition for hard coat layer prepared using each of the above-mentioned materials on the light-transmitting substrate, and if necessary, dried, and irradiated with ionizing radiation. Alternatively, it can be formed by curing by heating or the like. In addition, the preparation method of the said composition for hard-coat layers, the formation method of a coating film, etc. can mention the method similar to the low refractive index layer mentioned above.

The antiglare layer is a layer having a concavo-convex shape formed on the surface thereof by an encapsulated antiglare agent, a layer having internal scattering properties, or a layer having no concavo-convex shape and having only internal scattering properties. It has a function of reducing external light reflection on the surface of the optical laminate, and a function of diffusing transmitted light from the inside and reflected light from the outside.
It does not specifically limit as said anti-glare layer, For example, what is formed with the composition for anti-glare phases containing resin and an anti-glare agent is mentioned.

In the optical layered body of the present invention, the antiglare layer has an average particle diameter of R (μm) as fine particles as an antiglare agent, and a ten-point average roughness of irregularities of the antiglare layer is Rz (μm). When the average unevenness of the glare layer is Sm (μm) and the average inclination angle of the unevenness is θa, the following formula:
30 ≦ Sm ≦ 600
0.05 ≦ Rz ≦ 1.60
0.1 ≦ θa ≦ 2.5
0.3 ≦ R ≦ 15
It is preferable to satisfy all of these simultaneously.

Further, according to another preferred embodiment of the present invention, the antiglare layer has Δn = | n1−n2 | <0.1 when the refractive indexes of the antiglare agent and the resin are n1 and n2, respectively. It is preferable that the haze value in the antiglare layer is 55% or less.
The film thickness (at the time of curing) of the antiglare layer is preferably 0.1 to 100 μm, a more preferable lower limit is 0.8 μm, and a more preferable upper limit is 10 μm. When the film thickness is within this range, the function as an antiglare layer can be sufficiently exhibited.

Examples of the antiglare agent include fine particles. The shape is not particularly limited, such as a true spherical shape or an elliptical shape, but a true spherical shape is preferably used.

When the antiglare agent is fine particles, it may be made of an inorganic material or an organic material. The fine particles exhibit antiglare properties, and are preferably transparent. The particle size of the fine particles is about 0.1 to 20 μm when measured by a coal counter method.
Specific examples of the fine particles made of the inorganic material include amorphous beads and spherical silica beads.
Specific examples of fine particles made of an organic material include styrene beads (refractive index 1.59), melamine beads (refractive index 1.57), acrylic beads (refractive index 1.49), and acrylic-styrene. Beads (refractive index 1.53 to 1.58), benzoguanamine-formaldehyde condensate beads (refractive index 1.66), melamine-formaldehyde condensate beads (refractive index 1.66), polycarbonate beads (refractive index 1.57) Polyethylene beads (refractive index 1.50), polyvinyl chloride beads (refractive index 1.60), and the like. The fine particles made of the organic material may have a hydrophobic group on the surface thereof.

As content of the said glare-proof agent in the said glare-proof layer, it is preferable that it is 0.1-30 mass parts with respect to 100 mass parts of resin in this glare-proof layer, and a more preferable minimum is 1 mass part, A more preferred upper limit is 25 parts by mass.

The resin in the antiglare layer is not particularly limited. For example, an ionizing radiation curable resin, an ionizing radiation curable resin and a solvent which are resins cured by ultraviolet rays or electron beams similar to the resin described in the hard coat layer described above. Examples thereof include a mixture with a dry resin, a thermosetting resin, and the like.

The hard coat layer and the antiglare layer described above may further contain a known antistatic agent, a high refractive index agent, a high hardness / low curl material such as colloidal silica, and the like.
The optical laminate of the present invention having a structure in which the hard coat layer or the antiglare layer is formed between the light transmissive substrate and the low refractive index layer further comprises the hard coat layer or the antiglare layer, and light. A structure in which an antistatic layer made of a known antistatic agent and a binder resin is formed between the transparent substrate or the low refractive index layer may be used.

The optical layered body of the present invention has at least a low-refractive index layer on the light-transmitting substrate, and as necessary, in addition to the above-described hard coat layer or antiglare layer, Other hard coat layers, antifouling layers, high refractive index layers, medium refractive index layers and the like may be provided. The antifouling layer, the high refractive index layer, and the medium refractive index layer are prepared by adding a commonly used antifouling agent, a high refractive index agent, a medium refractive index agent, a low refractive index agent or a resin, Each layer may be formed by a known method.

The total light transmittance of the optical layered body of the present invention is preferably 90% or more. If it is less than 90%, color reproducibility and visibility may be impaired when it is mounted on the display surface. The total light transmittance is more preferably 95% or more, and still more preferably 98% or more.
The haze of the optical layered body of the present invention is preferably less than 1%, and more preferably less than 0.5%. When it has the said glare-proof layer, it is preferable that the haze of the optical laminated body of this invention is less than 80%. The antiglare layer may be composed of a haze due to internal diffusion and a haze due to an uneven shape on the outermost surface, and the haze due to internal diffusion is preferably 3.0% or more and less than 79%, preferably 10% or more and less than 50%. It is more preferable that The haze on the outermost surface is preferably 1% or more and less than 35%, more preferably 1% or more and less than 20%, still more preferably 1% or more and less than 10%.

In the method for producing an optical laminate of the present invention, the hard coat layer composition or the antiglare layer composition described above is applied onto a light-transmitting substrate as necessary to form a hard coat layer or an antiglare layer. Examples of the method include a step of forming, and a step of forming the low refractive index layer by applying the above-described composition for a low refractive index layer on the formed hard coat layer or antiglare layer.
The method for forming the hard coat layer, the antiglare layer and the low refractive index layer is as described above.

The optical layered body of the present invention can be made into a polarizing plate by providing the optical layered body according to the present invention on the surface of the polarizing element opposite to the surface where the low refractive index layer is present in the optical layered body. . Such a polarizing plate is also one aspect of the present invention.

The polarizing element is not particularly limited, and examples thereof include a polyvinyl alcohol film, a polyvinyl formal film, a polyvinyl acetal film, and an ethylene-vinyl acetate copolymer saponified film that are dyed and stretched with iodine or the like.
In the laminating process of the polarizing element and the optical laminate of the present invention, it is preferable to saponify the light-transmitting substrate (preferably a triacetyl cellulose film). By the saponification treatment, the adhesiveness is improved and an antistatic effect can be obtained.

The present invention is also an image display device including the optical laminate or the polarizing plate on the outermost surface. The image display device may be a non-self-luminous image display device such as an LCD, or a self-luminous image display device such as a PDP, FED, ELD (organic EL, inorganic EL), or CRT.

The LCD, which is a typical example of the non-self-luminous type, includes a transmissive display body and a light source device that irradiates the transmissive display body from the back surface. When the image display device of the present invention is an LCD, the optical laminate of the present invention or the polarizing plate of the present invention is formed on the surface of this transmissive display.

In the case where the present invention is a liquid crystal display device having the optical laminate, the light source of the light source device is irradiated from the lower side of the optical laminate. Note that in the STN liquid crystal display device, a retardation plate may be inserted between the liquid crystal display element and the polarizing plate. An adhesive layer may be provided between the layers of the liquid crystal display device as necessary.

The PDP which is the self-luminous image display device includes a front glass substrate (electrode is formed on the surface) and a rear glass substrate (electrodes and minute electrodes) disposed with a discharge gas sealed between the front glass substrate and the front glass substrate. Are formed on the surface, and red, green, and blue phosphor layers are formed in the groove). In the case where the image display device of the present invention is a PDP, the surface of the surface glass substrate or the front plate (glass substrate or film substrate) is provided with the optical laminate described above.

The self-luminous image display device is an ELD device that emits light when a voltage is applied, such as zinc sulfide or a diamine substance: a phosphor is deposited on a glass substrate, and the voltage applied to the substrate is controlled. It may be an image display device such as a CRT that converts light into light and generates an image visible to the human eye. In this case, the optical laminated body described above is provided on the outermost surface of each display device as described above or the surface of the front plate.

In any case, the image display apparatus of the present invention can be used for display display of a television, a computer, a word processor, or the like. In particular, it can be suitably used for the surface of high-definition image displays such as CRT, liquid crystal panel, PDP, ELD, FED and the like.

The optical layered body of the present invention has a low refractive index layer excellent in hardness, surface uniformity and low refractive index performance and excellent in optical characteristics without whitening, and thus has scratch resistance, antireflection performance, transparency, etc. It has excellent optical characteristics.
Therefore, the optical laminate of the present invention is suitably applied to a cathode ray tube display (CRT), a liquid crystal display (LCD), a plasma display (PDP), an electroluminescence display (ELD), a field emission display (FED), and the like. be able to.

The contents of the present invention will be described with reference to the following examples, but the contents of the present invention should not be construed as being limited to these embodiments. Unless otherwise specified, “part” and “%” are based on mass.

(Preparation of composition for forming hard coat layer)
The components shown below were mixed to prepare a composition for forming a hard coat layer.
Urethane acrylate (UV1700B, manufactured by Nihon Gosei) 5 parts by mass isocyanuric acid-modified triacrylate (M315, manufactured by Toagosei Co., Ltd.) 5 parts by mass polymerization initiator (Irgacure 184; manufactured by Ciba Specialty Chemicals)
0.4 parts by mass methyl ethyl ketone 10 parts by mass

(Preparation of composition for low refractive index layer)
(Preparation Example 1)
The following components were mixed to prepare a composition for low refractive index layer (1).
Hollow treated silica fine particles (solid content of silica fine particles: 20% by mass solution; methyl isobutyl ketone, average particle size: 50 nm) 25 parts by mass fluorine atom-containing polymer (Daikin Industries, AR110, refractive index of about 1.39) , Weight average molecular weight 150,000, solid content 15% by weight solution methyl isobutyl ketone) 26.6 parts by mass Pentaerythritol triacrylate (PETA) 1 part by mass antifouling agent (manufactured by Degussa, TEGORad 2600) 0.5 parts by mass polymerization initiator (Irgacure 127; manufactured by Ciba Specialty Chemicals)
0.5 parts by weight MIBK 160 parts by weight N-butanol 40 parts by weight

(Preparation Example 2)
The following components were mixed to prepare a low refractive index layer composition (2).
Hollow treated silica fine particles (solid content of silica fine particles: 20% by mass solution; methyl isobutyl ketone, average particle size: 50 nm) 25 parts by mass fluorine atom-containing polymer (Daikin Industries, AR110, refractive index of about 1.39) , Weight average molecular weight 150,000, solid content 15 mass% solution methyl isobutyl ketone) 26.6 mass parts pentaerythritol triacrylate (PETA) 1 mass part antifouling agent (Degussa, TEGORad 2500) 0.5 mass parts polymerization initiator (Irgacure 127; manufactured by Ciba Specialty Chemicals)
0.5 parts by weight MIBK 160 parts by weight N-butanol 40 parts by weight

(Preparation Example 3)
The following components were mixed to prepare a composition for low refractive index layer (3).
Hollow treated silica fine particles (solid content of silica fine particles: 20% by mass solution; methyl isobutyl ketone, average particle size: 50 nm) 25 parts by mass fluorine atom-containing polymer (Daikin Industries, AR110, refractive index of about 1.39) , Weight average molecular weight 150,000, solid content 15% by weight solution methyl isobutyl ketone) 13.3 parts by weight pentaerythritol triacrylate (PETA) 3 parts by weight antifouling agent (manufactured by Degussa, TEGORad 2600) 0.5 parts by weight polymerization initiator (Irgacure 127; manufactured by Ciba Specialty Chemicals)
0.5 parts by weight MIBK 160 parts by weight N-butanol 40 parts by weight

(Preparation Example 4)
The following components were mixed to prepare a composition for low refractive index layer (4).
Hollow treated silica fine particles (solid content of the silica fine particles: 20% by mass solution; methyl isobutyl ketone, average particle size: 50 nm) 25 parts by mass fluorine atom-containing polymer (manufactured by Daikin Industries, Ltd., AR110, refractive index: about 1. 39, weight average molecular weight 100,000, solid content 15% by mass solution methyl isobutyl ketone) 26.6 parts by mass pentaerythritol triacrylate (PET) 1 part by mass antifouling agent (manufactured by Degussa, TEGORad 2600 0.5 parts by mass polymerization initiator) (Irgacure 127; manufactured by Ciba Specialty Chemicals)
0.5 parts by weight MIBK 160 parts by weight N-butanol 40 parts by weight

(Preparation Example 5)
The following components were mixed to prepare a composition for low refractive index layer (5).
Hollow treated silica fine particles (solid content of the silica fine particles: 20% by mass solution; methyl isobutyl ketone, average particle size: 50 nm) 25 parts by mass fluorine atom-containing polymer (manufactured by Daikin Industries, Ltd., AR110, refractive index: about 1. 39, weight average molecular weight 100,000, solid content 15% by weight solution methyl isobutyl ketone) 26.6 parts by mass Dipentaerythritol triacrylate (DPHA) 1 part by mass antifouling agent (manufactured by Degussa, TEGORad 2600) 0.5 parts by mass polymerization Initiator (Irgacure 127; manufactured by Ciba Specialty Chemicals)
0.5 parts by weight MIBK 160 parts by weight N-butanol 40 parts by weight

(Preparation Example 6)
The following components were mixed to prepare a composition for low refractive index layer (6).
Hollow treated silica fine particles (solid content of silica fine particles: 20% by mass solution; methyl isobutyl ketone, average particle size: 50 nm) 2.5 parts by mass of fluorine atom-containing polymer (Daikin Industries, AR110 modified, refractive index approx. 1.39, weight average molecular weight 100,000, solid content 15% by weight solution methyl isobutyl ketone) 26.6 parts by mass Pentaerythritol triacrylate (PETA) 1 part by mass antifouling agent (manufactured by Degussa, TEGORad 2600) 0.5 parts by mass Polymerization initiator (Irgacure 127; manufactured by Ciba Specialty Chemicals)
0.5 parts by weight MIBK 160 parts by weight N-butanol 40 parts by weight

(Preparation Example 7)
The following components were mixed to prepare a composition for low refractive index layer (7).
Hollow treated silica fine particles (solid content of silica fine particles: 20% by mass solution; methyl isobutyl ketone, average particle size: 50 nm) 2.5 parts by mass of fluorine atom-containing polymer (JSR, JN35, refractive index of about 1. 41, weight average molecular weight 3
Methyl, 15% solid solution methyl isobutyl ketone) 26.6 parts by mass Pentaerythritol triacrylate (PETA) 1 part by mass antifouling agent (DEGOSA, TEGORad 2600) 0.5 parts by mass polymerization initiator (Irgacure 127; Ciba・ Specialty Chemicals)
0.5 parts by weight MIBK 160 parts by weight N-butanol 40 parts by weight

(Preparation Example 8)
The following components were mixed to prepare a low refractive index layer composition (8).
Hollow treated silica fine particles (solid content of silica fine particles: 20% by mass solution; methyl isobutyl ketone, average particle size: 50 nm) 25 parts by mass fluorine atom-containing polymer (Daikin Industries, AR110, refractive index of about 1.39) , Weight average molecular weight 150,000, solid content 15% by weight solution methyl isobutyl ketone) 26.6 parts by mass antifouling agent (manufactured by Degussa, TEGORad 2600) 0.5 parts by mass polymerization initiator (Irgacure 127; Ciba Specialty Chemicals) Made)
0.5 parts by weight MIBK 160 parts by weight N-butanol 40 parts by weight

(Preparation Example 9)
The following components were mixed to prepare a composition for low refractive index layer (9).
Hollow treated silica fine particles (solid content of silica fine particles: 20 mass% solution; methyl isobutyl ketone, average particle size: 50 nm) 25 mass parts pentaerythritol triacrylate (PETA) 1 mass part antifouling agent (manufactured by Degussa, TEGORad2600) 0.5 parts by mass polymerization initiator (Irgacure 127; manufactured by Ciba Specialty Chemicals)
0.5 parts by weight MIBK 160 parts by weight N-butanol 40 parts by weight

(Preparation Example 10)
The following components were mixed to prepare a composition for low refractive index layer (10).
Hollow treated silica fine particles (solid content of silica fine particles: 20% by mass solution; methyl isobutyl ketone, average particle size: 50 nm) 25 parts by mass fluorine atom-containing polymer (Daikin Industries, AR110, refractive index of about 1.39) , Weight average molecular weight 150,000, solid content 15 mass% solution methyl isobutyl ketone) 26.6 mass parts pentaerythritol triacrylate (PETA) 1 mass part antifouling agent (manufactured by Dainippon Ink Industries, Ltd., MCF350, fluororesin) 0.5 parts by mass polymerization initiator (Irgacure 127; manufactured by Ciba Specialty Chemicals)
0.5 parts by weight MIBK 160 parts by weight N-butanol 40 parts by weight

(Preparation Example 11)
The following components were mixed to prepare a composition for low refractive index layer (11).
Hollow treated silica fine particles (solid content of silica fine particles: 20% by mass solution; methyl isobutyl ketone, average particle size: 50 nm) 25 parts by mass fluorine atom-containing polymer (Daikin Industries, AR110, refractive index of about 1.39) , Weight average molecular weight 150,000, solid content 15% by weight solution methyl isobutyl ketone) 26.6 parts by mass pentaerythritol triacrylate (PET) 1 part by mass antifouling agent (GE Toshiba Silicone, TSF4421, silicone system (in side chain) No polymerizable unsaturated double bond)) 0.5 parts by mass polymerization initiator (Irgacure 127; manufactured by Ciba Specialty Chemicals)
0.5 parts by weight MIBK 160 parts by weight N-butanol 40 parts by weight

Example 1
A wet weight 30 g / m ² (dry weight 15 g / m ² ) of the composition for a hard coat layer was applied to one side of a cellulose triacetate film (thickness 80 μm). It dried for 30 seconds at 50 degreeC, and irradiated the ultraviolet-ray 50mJ / cm < ² >, and formed the hard-coat layer.
Next, the composition for low refractive index layer (1) was applied on the formed hard coat layer so that the film thickness after drying (40 ° C. × 1 minute) was 0.1 μm. Then, using an ultraviolet irradiation device (Fusion UV System Japan Co., Ltd., light source H bulb), an ultraviolet ray was irradiated at an irradiation dose of 192 mJ / m ² and cured to obtain an optical laminate. The film thickness was adjusted so that the minimum value of reflectivity was around 550 nm.

(Examples 2-7, Comparative Examples 1-4)
Optical laminated bodies according to Examples 2 to 7 are obtained in the same manner as in Example 1 except that the low refractive index layer composition (1) is replaced with the low refractive index layer compositions (2) to (7). It was. Moreover, the optical laminated body which concerns on Comparative Examples 1-4 similarly to Example 1 except having replaced the composition for low refractive index layers (1) with the composition for low refractive index layers (8)-(11). Got.

(Evaluation)
Each evaluation shown below was performed about the optical laminated body obtained by the Example and the comparative example. The results are shown in Table 1.

(Measurement of reflectance)
A black tape for preventing the back surface reflection of each of the obtained optical laminates was pasted, and from the surface of the low refractive index layer, a spectral reflectance measuring machine “PC-3100” manufactured by Shimadzu Corporation was used, and a wavelength range of 380 to 780 nm. The minimum reflectance was measured. The results were evaluated according to the following criteria.
Evaluation criteria ○: Minimum reflectance is less than 1.5% ×: Minimum reflectance is 1.5% or more

(Evaluation of whitening)
The haze value (%) of the low refractive index layer of each obtained optical laminate was measured according to JIS K-7136 using a haze meter (manufactured by Murakami Color Research Laboratory, product number: HM-150). The results were evaluated according to the following criteria.
○: Less than 0.5% ×: 0.5% or more

(Abrasion resistance test)
The surface of the obtained low refractive index layer of each optical laminate was subjected to 10 reciprocating frictions using # 0000 steel wool at a predetermined friction load of 300 g / cm ² , and then the presence or absence of peeling of the coating film was visually observed. The results were evaluated according to the following criteria.
○: No scratch ×: Scratch

(Coating surface)
A black tape is pasted on the surface of the film on which the low refractive index layer of each optical laminate is not formed, and the coated surface is visually observed with a three-wavelength lamp from the surface on which the low refractive index layer is formed. The results were evaluated according to the following criteria.
Evaluation criteria ○: The coated surface is uniform and clean ×: The coated surface is uneven due to color spots and streaks

(Anti-fouling property)
The surface of the obtained low refractive index layer of each optical laminate was written with an oil pen (Mackey, trade name, manufactured by ZEBRA), and then wiped off with a tissue. The state of the surface after wiping off was visually observed and evaluated according to the following criteria.
○: Completely wiped off ×: Not completely wiped off, leaving black marks

From Table 1, the optical laminated body of an Example was excellent in all of each evaluation of a reflectance, hardness, a coating surface, and antifouling property, and whitening did not generate | occur | produce in the low refractive index layer.
On the other hand, none of the optical laminates of the comparative examples were excellent in reflectance, hardness, coated surface and antifouling property.

Since the optical layered body of the present invention has a low refractive index layer having the above-described configuration, it has a low refractive index layer excellent in hardness, surface uniformity and low refractive index performance, and excellent in optical characteristics without whitening. And excellent optical properties such as scratch resistance, antireflection and transparency. Therefore, the optical laminate of the present invention is preferably applied to a cathode ray tube display (CRT), a liquid crystal display (LCD), a plasma display (PDP), an electroluminescence display (ELD), a field emission display (FED), and the like. Can do.

Claims (6)

An optical laminate having at least a low refractive index layer on a light transmissive substrate,
The low refractive index layer is formed using a composition for low refractive index layer containing hollow silica fine particles, fluorine atom-free polyfunctional monomer, fluorine atom-containing polymer and antifouling agent, and
The antifouling agent is a silanol compound having a segment represented by the following general formula (1).

In general formula (1), n is an integer of 2 to 10, m is an integer of 2 to 300, and R is a structure represented by the following general formula (2).

In general formula (2), x, y, z represents an integer of 0-20. Fluorine atom-free polyfunctional monomers are pentaerythritol tri (meth) acrylate, dipentaerythritol hexa (meth) acrylate, pentaerythritol (meth) tetraacrylate, dipentaerythritol penta (meth) acrylate, trimethylolpropane tri (meth) The optical laminate according to claim 1, which is at least one selected from the group consisting of acrylate, dipentaerythritol tetra (meth) acrylate, and isocyanuric acid-modified (meth) triacrylate. The optical laminate according to claim 1 or 2, wherein the refractive index of the low refractive index layer is less than 1.45. The optical laminate according to claim 1, 2 or 3, further comprising a hard coat layer or an antiglare layer between the light-transmitting substrate and the low refractive index layer. A polarizing plate comprising a polarizing element,
The polarizing plate comprises the optical laminate according to claim 1, 2, 3, or 4 on the surface of a polarizing element. An image display device comprising the optical laminate according to claim 1, 3, or 4 or the polarizing plate according to claim 5 on an outermost surface.