JP2000147208A - Antireflection material and polarizing film using same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an antireflection material which exhibits superior antireflection performance, prevents the reflection of sunlight and external light of a fluorescent lamp or the like in a display, can give a clear image free from glaring or the like without reducing image contrast and has optical stability, superior wear resistance, chemical resistance and contamination resistance. SOLUTION: A hard coat layer 12 containing at least a polymer using a urethane (meth)acrylate compound as a polymerizable component and nanoparticles having a high refractive index is disposed on one face or both faces of a transparent substrate 11 directly or by way of other layer. An antireflection film having an adjusted refractive index and comprising a monolayer or plural layers is then disposed on the hard coat layer 12.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal display (LCD), a plasma display (PDP),
The present invention relates to an antireflection material which is suitably used for an image display such as T, EL and the like, and is particularly excellent in antifouling property, antireflection, chemical resistance and abrasion resistance of an image portion, and a polarizing film using the same.

[0002]

2. Description of the Related Art Image display devices such as LCDs, PDPs, CRTs and ELs (hereinafter referred to as "displays") are widely used in various fields including televisions and computers, and are remarkable. Has evolved. In recent years, expectations are growing for the spread to mobile phones, PHS, and other various types of mobile terminals.

As displays for portable terminals, LCDs having features such as light weight, compactness and versatility are considered to dominate the market. However, these portable terminals are equipped with a touch panel and a plastic pen. What is operated by directly touching with a finger or a finger is becoming mainstream. Therefore, demands for abrasion resistance, chemical resistance, and prevention of dirt on the display surface are increasing. In addition, when these devices are used in relatively bright places including outdoor use, there is a strong demand for preventing reflection of external light such as sunlight or fluorescent light on a display, that is, antireflection. I have. At present, these demands are spreading not only to portable terminal devices but also to various displays ranging from small to large.

[0004]

In order to solve this problem, a high-refractive-index layer and a low-refractive-index layer are alternately formed on the surface of the display such that the outermost layer is a low-refractive-index layer.
A method has been developed to reduce the reflectance of the outermost surface of the display by forming a multilayer structure in which at least two layers are stacked. Examples of the material for the layer having a low refractive index include MgF ₂ and SiO ₂ , and examples of the material for the layer having a high refractive index include TiO ₂ , ZrO _{2, and the} like. It is laminated by a sol-gel method or the like. However, the vapor phase method is expensive in processing equipment and is not suitable for processing a large area, and the sol-gel method has problems in economical efficiency because coating and firing are repeated. In addition, as a method that can be manufactured at low cost, it has been proposed to form a film using a paint using these materials by a roll coater, printing, or the like. However, since the film thickness control on the order of 10 nm required for characteristics is not sufficient, There was a problem with color unevenness (interference unevenness).

[0005] An anti-reflection film provided with an anti-reflection layer as described above on a transparent substrate such as polyethylene terephthalate (PET) is used by being attached to a surface of a touch panel or the like operated by directly touching with a pen or a finger. In such cases, a high degree of wear resistance, chemical resistance, and contamination prevention are required. Usually, in order to satisfy these characteristics, a hard coat layer is provided between the transparent substrate and the antireflection layer. In order to improve the antireflection characteristics of the antireflection film, it is necessary to control the refractive index of this hard coat layer as well.

Optically, by increasing the refractive index of the hard coat layer, a certain anti-reflective material can be obtained by providing a conventional low refractive index layer made of silica or the like on the hard coat layer. In addition, the layer configuration of the antireflection material can be simplified. Further, in this case, since the layer requiring strict film pressure control is limited to only the low refractive index layer, production by the above-described roll coater or printing becomes possible. However, it is very difficult to satisfy the high refractive index of the hard coat layer and the durability such as abrasion resistance, chemical resistance, and light resistance as an anti-reflection film, and there has been no sufficient one so far. .

As the resin used for the hard coat layer, a transparent thermosetting resin, a thermoplastic resin, a radiation curing resin, or the like is usually used. Further, a crosslinking agent, a polymerization initiator, a polymerization accelerator, a viscosity modifier, and the like are used as needed. To increase the refractive index of the hard coat layer,
A method has been proposed in which ultrafine particles having a high refractive index are added to the binder resin. As a processing method, there has been reported a method in which the above resin and ultrafine particles are mixed together with an additive or a solvent, and the mixture is formed into a coating material by a coater or printing. According to these methods, the refractive index of the hard coat layer can be adjusted to some extent by the content of the ultrafine particles, but when the content is increased, the transparency becomes poor, or the abrasion resistance, chemical resistance, etc. There was a problem that durability deteriorated. In addition, with the increase in the content of the ultrafine particles, the ultrafine particles adhere to each other in a film forming process to form coarse particles, and there is a problem that the transparency is significantly reduced.

The present invention has been made in view of the above circumstances in the prior art, and has a multilayer structure having a hard coat layer having a high refractive index and excellent durability. And prevents reflection of external light such as fluorescent lamps, etc., exhibits excellent anti-reflection properties, and can obtain a clear image without glare without lowering the image contrast, light resistance, An object of the present invention is to provide an antireflection material having excellent chemical properties and abrasion resistance, and having durability even when used for a display or a touch panel for outdoor use. Further, the present invention also aims to provide a polarizing film using the antireflection material,
In this way, it is particularly intended to significantly improve the performance of a full-color liquid crystal display or the like.

[0009]

Means for Solving the Problems (1) Contents of antireflection material The present inventors have studied the dispersibility of high refractive index ultrafine particles in the hard coat layer and the durability of the hard coat layer such as abrasion resistance. As a result of overlapping, it has been found that combining a specific compound with high refractive index ultrafine particles is extremely effective. Therefore, the antireflection material of the present invention has been made based on the above-mentioned knowledge, and has a urethane (meth) acrylate compound and high refractive index ultrafine particles, directly or through another layer, on one or both surfaces of a transparent substrate. Is provided, and an antireflection film composed of a single layer or a plurality of layers whose refractive index is adjusted is provided on the hard coat layer. Hereinafter, more preferred embodiments of the present invention will be described in detail.

[0010]

DETAILED DESCRIPTION OF THE INVENTION Transparent substrate As the transparent substrate used for the antireflection material of the present invention, a known transparent film, glass, or the like can be used. Specific examples thereof include polyethylene terephthalate (PET), polyethylene naphthalate (PEN), triacetyl cellulose (TAC), polyacrylate,
Various resin films and quartz glass such as polyimide, polyether, polycarbonate, polysulfone, polyethersulfone, cellophane, aromatic polyamide, polyethylene, polypropylene, and polyvinyl alcohol,
A glass substrate such as soda glass can be suitably used. When used for PDP and LCD, PET, TA
C is preferred.

Although the higher the transparency of these transparent substrates, the better, the light transmittance (JIS C-6714) is preferably 80% or more, more preferably 90% or more. When the transparent substrate is used for a small and lightweight liquid crystal display, the transparent substrate is more preferably a film. The thickness of the transparent substrate is desirably thin from the viewpoint of weight reduction, but in consideration of the productivity, it is 1 to 700 μm.
It is suitable to use those having a range of 25 to 250 μm.

Further, the transparent substrate is subjected to a surface treatment such as an alkali treatment, a corona treatment, a plasma treatment, a fluorine treatment, a sputtering treatment, a surfactant, a silane coupling agent or the like, or a surface modification treatment such as a Si deposition. By doing so, the adhesiveness between the transparent substrate and the hard coat layer or another layer can be improved. Further, an antistatic layer may be provided on the surface of the transparent substrate in order to prevent dirt such as dust electrostatically adhering to the display surface. The antistatic layer is formed by depositing a metal such as aluminum or tin, or a metal oxide film such as ITO by vapor deposition, sputtering, etc., and applying antimony or the like to fine metal particles such as aluminum or tin or whisker or metal oxide such as tin oxide. Doped fine particles and whiskers, 7,
A charge transfer complex formed between 7,8,8-tetracyanoquinodimethane and an electron donor (donor) such as a metal ion or an organic cation as a filler is used as a polyester resin, an acrylic resin, an epoxy resin, or the like. To be provided by solvent coating, polypyrrole,
Polyaniline or the like doped with camphorsulfonic acid or the like can be provided by a method of providing the material by solvent coating or the like. The transmittance of the antistatic layer is preferably 80% or more for optical applications.

B. Hard coat layer The hard coat referred to in the present invention is a pencil hardness test (JIS
K5400) with a hardness of H or higher. Further, the high refractive index and the low refractive index referred to in the present invention refer to the relative refractive index between adjacent layers. Next, the hard coat layer in the present invention will be described. As the resin constituting the hard coat layer of the present invention, a resin that can be cured by radiation or heat or a combination thereof can be used, but it is essential that at least a urethane (meth) acrylate compound is contained. Thereby, both the refractive index of the hard coat layer and the strength of the layer can be increased.

The urethane compound is represented by Chemical Formula 1 or Chemical Formula 2. The urethane (meth) acrylate compound of Chemical Formula 1 is a compound having at least two (meth) acrylate groups in a reaction product of a hydroxyl group-containing (meth) acrylate compound and an isocyanate compound. The urethane (meth) acrylate compound of Chemical Formula 2 is a compound having at least two (meth) acrylate groups in a reaction product of a hydroxyl group-containing (meth) acrylate compound, an isocyanate compound, and a polyol compound. As a method for obtaining the urethane (meth) acrylate, any known method can be used.

[0015]

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[0016]

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In the formula, R ₁ represents a hydrogen atom or CH ₃ , X represents an isocyanate residue, and R ₂ and Y represent a polyhydric alcohol residue. k represents an integer of 1 to 5, l represents an integer of 1 to 3, m represents an integer of 1 to 2, and n represents an integer of 1 to 6. However, k and l, and k, l and m are never 1 at the same time.

Examples of the hydroxyl group-containing (meth) acrylate compound include glycerin (meth) acrylate, trimethylolpropane (meth) acrylate, pentaerythritol (meth) acrylate, glycerin di (meth) acrylate, trimethylolpropane di (meth) acrylate, Examples thereof include pentaerythritol tri (meth) acrylate, ditrimethylolpropane tri (meth) acrylate, and dipentaerythritol penta (meth) acrylate. These can be used alone or in combination of two or more.

As the isocyanate compound, o-tolyl isocyanate, p-tolyl isocyanate, 4-diphenylmethane isocyanate, 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate,
4,4-diphenylmethane diisocyanate, m-xylylene diisocyanate, p-xylylene diisocyanate, tetramethyl xylylene diisocyanate, biphenylene diisocyanate, 1,5-naphthylene diisocyanate, o-tolidine diisocyanate, hexamethylene diisocyanate, 4,4'- Methylenebiscyclohexyl isocyanate, isophorone diisocyanate, trimethylhexamethylene diisocyanate, 1,
Examples thereof include 3- (isocyanatomethyl) cyclohexane, and polycondensates thereof such as burettes and nurates. These can be used alone or in combination of two or more. Particularly preferred are a nulated product of tolylene diisocyanate, xylylene diisocyanate and hexamethylene diisocyanate, a nulated product of isophorone diisocyanate, and the like.

Examples of the polyol compound include aliphatic polyhydric alcohols such as ethylene glycol, propylene glycol, neopentyl glycol, 1,6-hexanediol, glycerin, trimethylolpropane, carboxylic acid-containing polyols, ethylene oxide of various bisphenols and propylene. An aromatic polyhydric alcohol such as an oxide reactant, an ethylene oxide and a propylene oxide reactant of bisphenolfluorene, and a (meth) acryloyl group in a molecule represented by Chemical formula 2 regardless of an aliphatic or aromatic compound Polyol. Particularly preferred are dimethylolpropionic acid, dimethylolbutanoic acid, bisphenoxyethanolfluorene and the like.

In the present invention, in order to control the properties of paints and coating films such as viscosity, crosslink density, heat resistance and chemical resistance, polymerizable non-polymerizable compounds such as acryloyl group, methacryloyl group, acryloyloxy group and methacryloyloxy group are used. A composition in which monomers, oligomers, and prepolymers having a saturated bond are appropriately mixed is used as needed. Examples of the monomer include styrene, methyl acrylate, methyl methacrylate, methoxypolyethylene methacrylate, cyclohexyl methacrylate, phenoxyethyl methacrylate, ethylene glycol dimethacrylate, dipentaerythritol hexaacrylate, trimethylolpropane trimethacrylate, and the like. Examples of the oligomer and prepolymer include acrylates such as polyester acrylate, polyurethane acrylate, epoxy acrylate, polyether acrylate, alkyd acrylate, melamine acrylate, and silicone acrylate, unsaturated polyester, and epoxy compounds. These may be used alone or in combination. Monomers are preferred if the flexibility of the cured film is required, and in order to further reduce the crosslink density, it is preferable to use a monofunctional or difunctional acrylate monomer. When severe durability such as resistance, abrasion resistance and solvent resistance is required, it is preferable to increase the amount of the monomer and use a trifunctional or higher functional acrylate monomer.

At least urethane (meth) as described above
The hard coat layer is formed by curing the composition containing the acrylate compound. In order to cure such a resin, for example, radiation such as ultraviolet rays, electron beams, or X-rays may be applied, but a polymerization initiator can be appropriately added as needed. As the polymerization initiator, any one can be used without particular limitation as long as it generates an active radical by heat or energy rays such as visible light and ultraviolet light. Examples of polymerization initiators that generate active radicals by heat include azo compounds such as 2,2′-azobis (2,4-dimethylvaleronitrile), benzoyl peroxide,
Organic peroxides such as lauroyl peroxide can be used. Examples of polymerization initiators that generate active radicals by energy rays include diethoxyacetophenone,
-Hydroxy-2-methyl-1-phenylpropane-1
Acetophenones such as -one, benzyldimethyl ketal, 1-hydroxycyclohexyl-phenylketone, 2-methyl-2-morpholino (4-thiomethylphenyl) propan-1-one, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether Benzoin ethers such as benzoin isobutyl ether, benzophenone, methyl o-benzoylbenzoate, 4-phenylbenzophenone, 4-benzoyl-
4'-methyl-diphenyl sulfide, 4-benzoyl-N, N-dimethyl-N- [2- (1-oxo-2-
Benzophenones such as propenyloxy) ethyl] benzenemethananium bromide and (4-benzoylbenzyl) trimethylammonium chloride; thioxanthones such as 2,4-diethylthioxanthone and 1-chloro-4-dichlorothioxanthone; -Trimethylbenzoyldiphenylbenzoyl oxide,
And a cationic polymerization initiator represented by the following chemical formula. These can be used alone or in combination of two or more.

[0023]

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Further, as an accelerator (sensitizer), N, N-
Amine compounds such as dimethyl paratoluidine and 4,4′-diethylaminobenzophenone can be used as a mixture. The content of the polymerization initiator is preferably from 0.1 to 10% by weight, and more preferably from 3 to 7% by weight, based on the radiation-curable resin. If the amount of the polymerization initiator is too large, unreacted decomposition products of the polymerization initiator may cause a decrease in the strength of the layer or cause coloring of the resin. Conversely, if the amount is too small, the resin does not solidify. Also visible light,
In the case of a polymerization initiator that generates active radicals by energy rays such as ultraviolet rays, when using a filler that absorbs in the wavelength range of irradiation energy rays, it is necessary to increase the ratio of the polymerization initiator.

Volume shrinkage rate due to hardening of the hard coat layer using the above radiation curable resin (calculated by the following method)
Is desirably 20% or less. If the volume shrinkage is more than 20%, the curl becomes remarkable when the transparent substrate is a film, and the adhesiveness of the hard coat layer decreases when the substrate is a rigid material such as glass.

[0026]

## EQU1 ## Volume shrinkage: D = (S−S ′) / S × 100 S: specific gravity before curing S ′: specific gravity after curing (specific gravity is measured by the B method pycnometer method of JIS K-7112)

In the hard coat layer of the present invention, a stabilizer (thermal polymerization inhibitor) such as hydroquinone, p-benzoquinone, and t-butylhydroquinone may be added to the radiation-curable resin. The amount of addition is preferably in the range of 0.1 to 5.0% by weight based on the radiation-curable resin.

In addition, a thermosetting resin can be used in combination with the hard coat layer if necessary.
Phenol resin, furan resin, xylene / formaldehyde resin, ketone / formaldehyde resin, urea resin, melamine resin, aniline resin, alkyd resin, unsaturated polyester resin, epoxy resin and the like can be mentioned. These may be used alone or in combination. When the transparent substrate is a plastic film,
The thermosetting temperature cannot be set high. In particular, PE
When T or TAC is used, it is desirable that the thermosetting resin used can be cured at 100 ° C. or lower.

The higher the transparency of the curable resin used for the hard coat layer, the better the light transmittance (JIS C-67).
As 14), like the transparent substrate, 80% or more, particularly 90%
% Or more is preferable. Although the transparency of the antireflection material is affected by the refractive index of the curable resin, the refractive index is 1.5%.
A range of 5 to 1.70, particularly a range of 1.60 to 1.70 is preferable. If the range is exceeded, the antireflection effect is impaired.

In order to increase the refractive index of the resin, a resin containing an aromatic ring or a halogenated element such as Br, I, or Cl is selected. Examples of the resin containing an aromatic ring include styrene resins such as polystyrene, PET, and polycarbonate of bisphenol A. Examples of the resin containing a halogenated element include polyvinyl chloride and polytetrabromobisphenol A glycidyl ether. Further, resins containing S, N, P and the like also have a high refractive index, and examples thereof include polyvinyl pyridine and polybisphenol S glycidyl ether.

High refraction to binder resin of hard coat layer
Adjusts the refractive index of the hard coat layer by including ultra-fine particles of refractive index
Can improve the anti-reflection effect
You. As the ultra-fine particles of high refractive index, TiO₂(Refractive index: n
= 2.3-2.7), CeO ₂(N = 1.95), Zn
O (n = 1.9), Sb₂O₅(N = 1.71), Sn
O₂(N = 1.95), ITO (n = 1.95), Y₂
O₃(N = 1.87), La₂O₃(N = 1.95),
ZrO₂(N = 2.05), Al₂O₃(N = 1.6
3), HfO₂(N = 2.00), Ta₂O₅Etc.
Can be These ultrafine particles have a particle size of 30 nm or less.
Use as a lower sol, alone or in combination
Can be.

The ultrafine particles can be converted into a sol by a known method. For example, a colloidal solution of TiO ₂ is a TiO ₂ powder so as to be 1 to 40 wt% concentration was suspended in a dispersion of water or an organic solvent, and in the range of 1 to 7 pH by adding an acid, It is carried out by contacting with a cation exchanger or by adding an alkali to adjust the pH to within a range of 7 to 14, and then bringing the mixture into contact with an anion exchanger. The contact with the ion exchanger is performed until the suspension of the titania powder becomes sol. In the range of room temperature to 200 ° C., the TiO ₂ fine particles are uniformly dispersed by the treatment for 0.5 to 200 hours. It becomes titania sol.

As the organic solvent used as the dispersion, solvents such as alcohols, glycols, esters, and aromatics can be used. Specifically, methanol, ethanol, propanol, ethylene glycol, glycerin,
Acetone, methyl ethyl ketone, methyl cellosolve, ethyl cellosolve, dimethylformamide, N-methyl-
2-pyrrolidone and the like can be mentioned. Further, by treating the surface of the titanium oxide particles with a silane coupling agent, a titanium coupling agent, a surfactant, a higher fatty acid or a salt thereof, etc., a low-polar organic solvent such as xylene or toluene is dispersed in a titania sol. You can also.

As the acid to be added for adjusting the pH, monobasic acids such as hydrochloric acid, nitric acid, acetic acid, chloric acid, chloroacetic acid, etc.
Examples thereof include dibasic acids such as sulfuric acid and tribasic acids such as phosphoric acid, and these acids can be used alone or in combination of two or more. Examples of the alkali include sodium hydroxide, potassium hydroxide, hydroxides of alkali metal elements such as lithium hydroxide, ammonia, and nitrogen compounds such as tetramethylammonium hydroxide.
These alkalis can be used alone or in combination.

In producing the titania sol, the amount of acid or alkali added is 5 × with respect to one equivalent of titanium (Ti).
10 ^{−4 to} 0.05 equivalent, preferably 2.5 × 10 ⁻³
A range of -0.025 equivalents is good.

As the ion exchanger, any substance can be used as long as it has ion exchange ability. Examples of the cation exchanger include a strongly acidic or weakly acidic cation exchange resin, a chelate resin, an ion exchange membrane, and a zeolite. Examples of the anion exchanger include a strongly basic or weakly basic anion exchange resin, a chelate resin, and an ion exchange membrane. These ion exchangers can be used alone or in combination. When the ion exchanger is an ion exchange resin or zeolite is used in a proportion of 1~10L TiO ₂ with a 1 kg.

The titania sol obtained by the above method is
It is concentrated by distillation under reduced pressure or ultrafiltration or the like, and water or an organic solvent can be added thereto to prepare a titania sol suspension having a required composition. The sol suspension of the ultrafine particle filler in the present invention desirably uses an organic solvent. The particle size is preferably 30 nm or less, and more preferably 20 nm or less from the viewpoint of the transparency of the coating film.

In the present invention, as a method of providing a hard coat layer on one or both sides of a transparent substrate directly or via another layer, the urethane (meth) acrylate compound and high refractive index Or mix an organic solvent and paint it with a paint shaker, sand mill,
Pearl mill, ball mill, attritor, roll mill,
High-speed impeller disperser, jet mill, high-speed impact mill,
It is dispersed by ultrasonic dispersing machine etc. to make paint or ink, which is air doctor coating, blade coating, knife coating, reverse coating,
Transfer roll coating, gravure roll coating, kiss coating, cast coating,
Coating such as spray coating, slot orifice coating, calendar coating, electrodeposition coating, dip coating, die coating, relief printing such as flexo printing, intaglio printing such as direct gravure printing, offset gravure printing, lithographic printing such as offset printing, screen It is provided in a single layer or multiple layers on one or both sides of the transparent substrate by a printing method such as stencil printing such as printing. A method is required in which the coating layer or the printed layer is cured by irradiation or the like. When the radiation is an electron beam, 50 to 1000 KeV emitted from various electron beam accelerators such as Cockloft-Walton type, Bande graph type, Resonant transformation type, Insulating core transformer type, Linear type, Dynamitron type and High frequency type. An electron beam or the like having an energy of is used, and in the case of ultraviolet rays, an ultra-high pressure mercury lamp, a high pressure mercury lamp, a low pressure
Ultraviolet rays emitted from light rays such as a metal halide lamp can be used.

In order to improve the coating suitability or printability of paints and inks, if necessary, a leveling agent such as silicone oil, polyethylene wax, carnauba wax, higher alcohols, bisamides, oils and fats such as higher fatty acids, isocyanates, etc. Additives such as hardening agents, ultrafine particles of 0.1 μm or less, such as calcium carbonate, silica sol, and synthetic mica, can be used as appropriate. Further, an antistatic agent may be added to prevent dirt such as dust electrostatically adhering to the display surface. As the antistatic agent, the materials described for the above antistatic layer can be applied as they are.

The thickness of the hard coat layer is in the range of 1 to 10 μm, preferably in the range of 1 to 5 μm. When the hard coat layer is thinner than 1 μm, the hard coat layer is deteriorated in abrasion resistance or hardened poorly due to oxygen inhibition such as when an ultraviolet curable resin is used. If the thickness is more than 10 μm, curling may occur due to curing shrinkage of the resin,
Microcracks occur in the hard coat layer, and further, the adhesion to the transparent substrate is reduced.

C. Low refractive index layer In order to obtain an antireflection function, an antireflection film composed of a single layer or a plurality of layers whose refractive index is adjusted is provided on the hard coat layer. First, a single-layer antireflection film will be described. The composition of the antireflection film in the case of a single layer is not particularly limited, but it is preferable that the composition be such that its critical surface tension is 20 dyn / cm or less. Critical surface tension is 2
When it is larger than 0 dyn / cm, it becomes difficult to remove the dirt attached to the antireflection film. In order to improve the antireflection effect, the antireflection film has a refractive index of 1.20 to 1.
It is preferably 45. Materials having these characteristics include, for example, LiF (refractive index n = 1.4), Mg
F ₂ (n = 1.4), 3NaF · AlF ₃ (n = 1.
4), AlF ₃ (n = 1.4), Na ₃ AlF ₆ (n =
1.33), fine particles of inorganic materials such as SiO ₂ (n = 1.45), and inorganic low-reflection materials containing fluorine-based or silicone-based organic compounds contained in an acrylic resin or an epoxy-based resin. Organic low-reflection materials such as a plastic resin, a thermosetting resin, and a radiation-curable resin can be used. When a transparent substrate is made of a plastic film such as TAC or PET which is easily damaged by heat, a radiation-curable resin is preferable as the material of these antireflection films. Among them, a fluorine-based fluorinated material is particularly preferable in terms of preventing contamination.

Examples of the fluorine-containing material include a vinylidene fluoride copolymer, a fluoroolefin / hydrocarbon olefin copolymer, a fluorine-containing epoxy resin, and a fluorine-containing epoxy acrylate which are dissolved in an organic solvent and are easy to handle. , Fluorinated silicone, fluorinated alkoxysilane, TFRON AF1600 (manufactured by DuPont, refractive index n = 1.30), CYTOP (manufactured by Asahi Glass Co., Ltd., n = 1.34), 17FM (Mitsubishi Rayon Co., Ltd.) ), N = 1.35), Opstar JN-721
2 (manufactured by Nippon Synthetic Rubber Co., Ltd., n = 1.40), LR2
01 (manufactured by Nissan Chemical Industries, Ltd., n = 1.38). These can be used alone or in combination of two or more.

Also, 2- (perfluorodecyl) ethyl methacrylate, 2- (perfluoro-7-methyloctyl) ethyl methacrylate, 3- (perfluoro-7-methyloctyl) -2-hydroxypropyl methacrylate, 2- (perfluoro- 9-methyldecyl) ethyl methacrylate, 3- (perfluoro-8-methyldecyl)-
Fluorinated methacrylates such as 2-hydroxypropyl methacrylate, 3-perfluorooctyl-2-hydroxypropyl acrylate, 2- (perfluorodecyl)
Fluorine-containing acrylates such as ethyl acrylate and 2- (perfluoro-9-methyldecyl) ethyl acrylate, 3-perfluorodecyl-1,2-epoxypropane, 3- (perfluoro-9-methyldecyl) -1,2-
Examples include epoxides such as epoxypropane, and radiation-curable fluorine-containing monomers, oligomers, and prepolymers such as epoxy acrylate. These can be used alone or in combination of two or more.

However, although these are excellent in stain resistance, they have poor wetting properties, so that depending on the composition, the antireflection film repels on the hard coat layer, or the antireflection film peels off from the hard coat layer. Because problems may occur, acryloyl groups used as radiation-curable resins, methacryloyl groups, acryloyloxy groups, monomers having a polymerizable unsaturated bond such as methacryloyloxy groups, oligomers, prepolymers are appropriately mixed,
It is desirable to use.

Furthermore, a low-reflection material in which a sol in which ultrafine silica particles of 5 to 30 nm are dispersed in water or an organic solvent and a fluorine-based film-forming agent are mixed may be used. The sol obtained by dispersing the ultrafine silica particles of 5 to 30 nm in water or an organic solvent can be prepared by dealkalizing alkali metal ions in an alkali silicate by ion exchange or neutralizing the alkali silicate with a mineral acid. A known silica sol obtained by condensing an active silicic acid known by a method, etc., a known silica sol obtained by condensing an alkoxysilane with hydrolysis in an organic solvent in the presence of a basic catalyst, An organic solvent-based silica sol (organo silica sol) obtained by substituting water in the aqueous silica sol with an organic solvent by a distillation method or the like is used. These silica sols can be used in both aqueous and organic solvent systems. It is not necessary to completely replace water with an organic solvent when producing an organic solvent-based silica sol. The silica sol contains solids 0.5 to 50% strength by weight as SiO _2. Various structures such as spherical, needle-like, and plate-like structures can be used for the ultrafine silica particles in the silica sol.

As the film forming agent, alkoxysilane,
Hydrolysates of metal alkoxides and metal salts, fluorine-modified polysiloxanes, and the like can be used.
By using the above-mentioned film forming agent, the critical surface tension of the antireflection film is reduced, and the adhesion of oil can be suppressed.

Further, an antistatic agent may be added to the antireflection film to prevent contamination such as dust adhering to the display surface electrostatically, or an antistatic layer may be provided on the antireflection film. The thickness of the antistatic layer is desirably an optical film thickness that does not affect the antireflection effect. 10 nm if possible
The following is desirable. As the antistatic agent, the materials described for the above antistatic layer can be applied as they are.

The single-layer antireflection film of the present invention is made of the low-reflection material described above, and is formed by a wet coating method such as roll coating or printing, or a vapor deposition method such as vacuum deposition, sputtering, plasma CVD, or ion plating. It is provided on the hard coat layer by a method. When provided by a wet coating method, a leveling agent such as silicone oil, polyethylene wax, carnauba wax, a higher alcohol, a bisamide, a fatty acid such as a higher fatty acid, an isocyanate, etc., as necessary, in order to improve coating suitability or printability. And additives such as ultrafine particles of 0.05 μm or less, such as calcium carbonate, silica sol, and synthetic mica.

The thickness for the antireflection film to exhibit a good antireflection function can be calculated by a known calculation formula. According to a known document (Science Library, Physics 9 "Optics", pp. 70-72), when incident light is perpendicularly incident on the antireflection film, the antireflection film does not reflect the light and transmits 100%. It is said that the condition for performing the above operation should satisfy the following relational expression. In the formula, N ₀ is the refractive index of the antireflection film, Ns is the refractive index of the hard coat layer, h is the thickness of the antireflection film, and λ ₀ is the wavelength of light.

[0050]

[Number 2] _N 0 ^{= Ns 1/2} Equation _{(1) N 0 h = λ} 0/4 formula (2)

According to the above equation (1), the reflection of light is 100
It can be seen that in order to prevent the reflection, the material should be selected so that the refractive index of the antireflection film becomes the square root of the refractive index of the lower layer (hard coat layer). However, in practice, it is difficult to find a material that completely satisfies the formula, and a material as close as possible is selected. In the above equation (2), the optimum thickness of the antireflection film is calculated from the refractive index of the antireflection film selected in the equation (1) and the wavelength of light. For example, when the refractive index of the hard coat layer and the antireflection film are 1.50 and 1.38, respectively, and the wavelength of light is 550 nm (standard of luminosity), and these values are substituted into the above equation (2), The thickness of the film is 0.1 μm
It is calculated that the optical film thickness before and after, preferably in the range of 0.10 ± 0.01 μm is optimal. As described above, the anti-reflection film needs to be extremely thin and very evenly provided (in-plane variation in thickness causes color unevenness due to interference with the hard coat layer). Therefore, as a method for providing the antireflection film, a gas phase method is preferable.

Next, a case where the antireflection film is provided in a multilayer structure will be described. When the antireflection film is provided in multiple layers, one or a plurality of laminated structures in which a low refractive index layer is provided on a high refractive index layer, or a high refractive index layer is formed on a low refractive index layer followed by a low refractive index layer One or a plurality of laminated structures provided with layers are provided on the hard coat layer. In this case, the refractive index n of the high refractive index layer is higher than that of the hard coat layer and is 1.6.
It is preferably in the range of 5 to 2.70. Further, the refractive index of the low refractive index layer serving as the outermost layer is preferably in the range of 1.20 to 1.45, and the refractive index of the low refractive index layer serving as the lower layer (hard coat layer side) of the high refractive index layer is: The refractive index is preferably lower than the refractive index of the hard coat layer and higher than the low refractive index layer on the high refractive index layer, which is the upper layer, and is preferably in the range of 1.35 to 1.55.

For the high refractive index layer, the materials described in the description of the high refractive index ultrafine particles can be applied as they are. These can be directly provided on the hard coat layer or the low refractive index layer by a vapor phase method such as vapor deposition, CVD, sputtering, etc. A paint or ink mixed with a solvent or the like is provided on the hard coat layer or the low refractive index layer by, for example, a spin coater, a roll coater, printing, etc., and after drying, heat or radiation (in the case of ultraviolet light, the above-described photopolymerization (Using an initiator) and the like. The thickness of the high refractive index layer is 0.05 to 0.15 μ
Adjust to m.

The resin used for the high refractive index layer is not particularly limited as long as it is transparent, and a thermosetting resin, a thermoplastic resin, a radiation (including ultraviolet) curable resin, or the like can be used. Examples of the thermosetting resin include a phenol resin, a melamine resin, a polyurethane resin, a urea resin, a diallyl phthalate resin, a guanamine resin, an unsaturated polyester resin, an aminoalkyd resin, a melamine-urea cocondensation resin, a silicon resin, and a polysiloxane resin. A silicate oligomer obtained by hydrolysis and condensation of an alkoxysilane or the like, for example, an inorganic binder such as MKC silicate MS51 manufactured by Mitsubishi Chemical Corporation, or the like can also be used. To these resins, a crosslinking agent, a catalyst, a curing agent such as a polymerization initiator, a polymerization accelerator, a solvent, a viscosity modifier, an antistatic agent, and the like can be added as necessary.

Examples of the radiation-curable resin include (meth) acrylates of polyfunctional compounds such as polyester resins, polyether resins, acrylic resins, epoxy resins, alkyd resins, polybutadiene resins, spirol acetal resins, urethane resins, and polyhydric alcohols. And monofunctional monomers and polyfunctional monomers such as ethyl (meth) acrylate, ethylhexyl (meth) acrylate, styrene, methylstyrene and N-vinylpyrrolidone as reactive diluents.

When the above resin is used as an ultraviolet curable resin, acetophenones, benzophenones, α-amyloxime ester, Michler benzoyl benzoate, tetramethylthiuram monosulfide, thioxanthone, and the like can be used as photopolymerization initiators. N- as sensitizer
Butylamine, triethylamine and the like can be used as a mixture.

The material of the single-layer antireflection film described above can be applied as it is to the low refractive index layer which is the lower layer of the outermost layer and the lower layer of the high refractive index layer. Interface between the anti-reflection film and the hard coat layer (including the interface between each layer when the anti-reflection film is a multilayer)
For the purpose of improving the adhesive strength and coating suitability, an adhesive layer may be provided, or various surface treatments described for the transparent substrate may be applied. The thickness of the adhesive layer is preferably 30 nm or less.

(2) Contents of Polarizing Film A protective material is laminated via a polarizing substrate on the other surface of the transparent substrate of the antireflective material having the above-mentioned structure on which the hard coat layer and the antireflection film are not provided. A polarizing film can be constituted. Hereinafter, the details of the polarizing film of the present invention will be described.

A. Polarizing Substrate The polarizing substrate is composed of a material capable of forming a transparent film, and specifically, polyvinyl alcohol, polyvinylene, or the like can be used. Then, a polarizing substrate can be obtained by stretching such a material to form a film. For example, it is preferable to use a polyvinyl alcohol (PVA) film obtained by uniaxially stretching polyvinyl alcohol adsorbing iodine or a dye as the dichroic element. A polarizing substrate having a thickness of 10 to 80 μm is used. Specifically, the polarizing substrate can be obtained by stretching the PVA film about 3 to 4 times in the uniaxial direction and impregnating the stretched PVA film into higher-order iodine ions.

B. Protective material The PVA film obtained above is apt to tear due to lack of strength and the like, and has a drawback of a large shrinkage ratio with respect to a change in humidity. Therefore, the protective material is laminated on one surface of the polarizing substrate. You. Further, the transparent substrate of the anti-reflection material is also adhered to the other surface of the polarizing substrate and has the same function as the protective material. The protective material and the transparent substrate are bonded to both surfaces of the polarizing substrate with a polyester adhesive, a polyacrylic adhesive, a polyurethane adhesive, a polyvinyl acetate adhesive, or the like.

As the protective material, a transparent polymer compound film, for example, a cellulose film such as triacetyl cellulose, a polyester film, a polycarbonate film and the like can be used. Among them, triacetyl cellulose is particularly preferred. The thickness of the film is preferably from 10 to 2000 μm. In addition, it is preferable to improve the water resistance of these films by using a gelling agent such as boric acid, or performing heat treatment or formalization. Further, in order to improve the adhesion to the polarizing substrate, it is preferable to perform a surface treatment such as a saponification treatment or a corona treatment so that the surface energy of the bonding surface with the polarizing substrate becomes 50 dyn / cm or more.

The antireflection material and the polarizing film of the present invention will be described below in more detail with reference to the drawings. FIG. 1 is a schematic sectional view showing the structure of the antireflection material of the present invention. The antireflection material 10 has a structure in which a hard coat layer 12 is provided on one surface of a transparent substrate 11. The hard coat layer 1
Although an anti-reflection film is formed on the surface of No. 2, the illustration is omitted because the anti-reflection film is extremely thin (the same applies to the following). FIG. 2 is a schematic cross-sectional view showing the configuration of the polarizing film 20 of the present invention. An antireflection material 23 having a hard coat layer 22 on a transparent base 21 is provided on one surface of a polarizing base 24. Protective material 25 on the other side
Is provided.

FIG. 3 shows a structure of a liquid crystal display 30 in which the antireflection property is improved by the antireflection material of the present invention. The liquid crystal display 30 is formed by laminating a liquid crystal panel 31 on the upper surface and a back light source 32 such as a light guide plate (EL) or a lamp on the lower surface. As the liquid crystal panel 31, for example, a twisted nematic (TN) liquid crystal cell or the like can be used.

In the TN liquid crystal cell, an alignment film is formed by applying a polyimide solution on the transparent electrode surfaces 33 ′ and 34 ′ of two glass substrates 33, 34 having transparent electrodes having a desired pattern. This is oriented by a rubbing operation, and thereafter, a nematic liquid crystal 35 is injected between the glass substrates 33 and 34, and the periphery of the glass substrates 33 and 34 is sealed with an epoxy resin or the like. The nematic liquid crystal is twist-aligned by 90 ° by the action of the alignment film. On both sides of the two glass substrates of the TN liquid crystal cell opposite to the rear light source, both surfaces of the polarizing substrate 24 were protected by an antireflection material 23 having a hard coat layer 22 shown in FIG. A polarizing film 36 and a polarizing film 37 having no hard coat layer on the back light source side are provided.
Are adhered so that the polarization angles are twisted by 90 ° with each other, whereby the liquid crystal panel 31 is formed.

When a drive signal is applied to the transparent electrodes of the TN liquid crystal panel 31, an electric field is generated between the electrodes to which the signals are applied. At that time, due to the electronic anisotropy of the liquid crystal molecules,
Since the major axis of the liquid crystal molecules is parallel to the direction of the electric field, the optical rotatory power of the liquid crystal molecules is lost, and as a result, the light does not pass through the liquid crystal panel. The display of the image is recognized as visual information by contrast based on the difference in light transmission at this time. In the above liquid crystal display 30,
Light is transmitted through the liquid crystal panel 31, and an image can be displayed by giving a contrast between the light transmitting portion and the light non-transmitting portion of the liquid crystal panel 31.

FIG. 4 is a sectional view showing the structure of another liquid crystal display using the antireflection material 10 of the present invention. In FIG. 4, the liquid crystal panel 41 has two glass substrates 43, 4
4, a nematic liquid crystal 45 interposed therebetween, an upper polarizing film 46 having no hard coat layer, a lower polarizing film 47 having no hard coat layer and an upper polarizing film positioned outside the glass substrates 43 and 44 The anti-reflection material 10 is laminated on the reference numeral 46. The liquid crystal display 40 is formed by laminating a liquid crystal panel 41 and a back light source 32 located on the lower surface thereof.

[0067]

The present invention will be described in more detail by way of examples. In the following description, “parts” means “parts by weight”.

[Synthesis Example of Urethane (meth) acrylate] Synthesis Example 1 A mixture of pentaerythritol triacrylate and pentaerythritol tetraacrylate (having a hydroxyl value of 120)
mg KOH / g, hereinafter referred to as PETA) 940 g, hexamethylene diisocyanate (hereinafter referred to as HDI) 16
8 g and a few drops of dibutyltin dilaurate (hereinafter referred to as DBTL) were mixed, heated to 80 ° C., and reacted for about 5 hours to obtain a urethane acrylate of Synthesis Example 1.

Synthesis Example 2 Mixture of dipentaerythritol pentaacrylate and dipentaerythritol hexaacrylate (hydroxyl value 53 mg KOH / g, hereinafter referred to as DPPA) 2200
g, HDI 168 g, and a few drops of DBTL,
The reaction was carried out by heating to 0 ° C. for about 7 hours to obtain a urethane acrylate of Synthesis Example 2.

Synthesis Example 3 Synthesis was performed in the same manner as in Synthesis Example 1 except that 174 g of 2,4-tolylene diisocyanate was used instead of 168 g of HDI, to obtain a urethane acrylate of Synthesis Example 3.

Synthesis Example 4 Synthesis was performed in the same manner as in Synthesis Example 1 except that 250 g of 4,4′-diphenylmethane diisocyanate (hereinafter referred to as MDI) was used instead of 168 g of HDI, to obtain a urethane acrylate of Synthesis Example 4.

Synthesis Example 5 Synthesis was performed in the same manner as in Synthesis Example 1 except that 188 g of xylylene diisocyanate was used instead of 168 g of HDI, to obtain a urethane acrylate of Synthesis Example 5.

Synthesis Example 6 3200 g of DPPA, 666 g of a nullified product of isophorone diisocyanate, and a few drops of DBTL were mixed to give 8
The reaction was carried out by heating to 0 ° C. for about 7 hours to obtain a urethane acrylate of Synthesis Example 6.

Synthesis Example 7 Bisphenoxyethanol fluorene 438 g, MDI
500 g and a few drops of DBTL are mixed, heated to 80 ° C. and the reaction is allowed to proceed for about 3 hours, then 2350 g of DPPA
Was added, and the reaction was carried out at 80 ° C. for about 6 hours to obtain a urethane acrylate of Synthesis Example 7.

Synthesis Example 8 134 g of dimethylolpropionic acid, 500 g of MDI,
And a few drops of DBTL are mixed, heated to 80 ° C. and the reaction is allowed to proceed for about 6 hours, then 1050 g of PETA is added,
The reaction was performed at 80 ° C. for about 6 hours to obtain a urethane acrylate of Synthesis Example 8.

<Example 1> A coating liquid having the following composition was stirred with a disper for 15 minutes, and the mixed coating was applied to a transparent substrate of triacetyl cellulose (trade name: Fujitack UVD80) having a thickness of 80 µm and a transmittance of 92%. , Manufactured by Fuji Photo Film Co., Ltd., with a refractive index of 1.49), applied by a reverse coating method, dried at 100 ° C. for 2 minutes, and using one condensing high-pressure mercury lamp having an output of 120 w / cm. Ultraviolet irradiation was performed at an irradiation distance (distance from the center of the lamp to the coating surface) of 10 cm and at a processing speed (speed of the coating substrate with respect to the mercury lamp) of 5 m / min to cure the coating film. Thus, a hard coat layer having a thickness of 1.7 μm and a refractive index of 1.53 was formed. Then, a fluorine-containing silica sol (trade name: L
R201, manufactured by Nissan Chemical Industries, Ltd. (total solid content; 4
%, Solvent: ethanol / butyl cellosolve = 50/5
0, manufactured by Nissan Chemical Industry Co., Ltd.) on the hard coat layer by spin coating, dried at 100 ° C. for 1 minute, heat-cured at 120 ° C. for 6 hours, and cured to a thickness of 0.1
μm, refractive index 1.38, critical surface tension 11 dyn / cm
Was formed to obtain an antireflection material of the present invention having a reflectance of 1.4%.

[Formulation of Coating Solution] Sol of rutile type titanium dioxide and zirconium dioxide composite colloid (total solid content: 20%, solvent: methanol, average particle size: 10 to 15 nm, refractive index: 2.05, 225 parts by weight of TiO ₂ and ZrO ₂ ; 100/20) 248 parts ・ 48 parts of urethane (meth) acrylate of Synthesis Example 1 ・ 7 parts of polymerization initiator (trade name: Irgacure # 1800, manufactured by Ciba Specialty Chemical) ・ isopropyl alcohol 50 copies

<Examples 2 to 8> The present invention was carried out in the same manner as in Example 1 except that the urethane (meth) acrylate in the coating liquid for the hard coat layer was changed to the urethane (meth) acrylate in Synthesis Examples 2 to 8, respectively. Was obtained. The properties of the antireflection materials of Examples 2 to 8 are shown in Table 1 respectively.

<Comparative Example 1> In the coating liquid for the hard coat layer, urethane (meth) acrylate was used as a polyester resin (trade name: Byron 200, manufactured by Toyobo Co., Ltd.), and isopropyl alcohol was used as a mixed solvent of methyl ethyl ketone and toluene (1/1). A hard coat layer having a thickness of 3.0 μm was formed in the same manner as in Example 1 except that 1) was replaced. The obtained comparative antireflection material had a reflectance of 2.1% and a critical surface tension of 14 dyn / cm.

Comparative Example 2 A hard coat layer having a thickness of 3.0 μm was formed in the same manner as in Example 1 except that the filler (sol) of the hard coat layer was changed to the following pigment.
A comparative antireflective material having a reflectance of 2.7% was obtained. In addition,
The critical surface tension of the antireflection film was 13 dyn / cm.・ Silica sol (trade name: organosilica sol MIBK-
ST, manufactured by Nissan Chemical Industries, solid content 30%)

Comparative Example 3 A hard coat layer having a thickness of 3.0 μm was formed in the same manner as in Example 1 except that the filler (sol) of the hard coat layer was not used, and the reflectance was 2.2.
% Of a comparative anti-reflective material was obtained. The critical surface tension of the anti-reflection film was 18 dyn / cm.

Comparative Example 4 A thickness of 80 μm and a transmittance of 92%
Was used as an anti-reflection material for comparison. The critical surface tension of the surface is 36 dyn /
cm.

Using the antireflection materials 10 obtained in Examples 1 to 8 and Comparative Examples 1 to 4, the reflectance, abrasion resistance, chemical resistance,
Critical surface tension and stain resistance were measured and evaluated by the following methods. Further, using each of the antireflection materials 10 of Examples 1 to 8 and Comparative Examples 1 to 4, a polarizing film 20 with a hard coat layer having a configuration shown in FIG. 2 was produced. Next, the polarizing film 20 with the hard coat layer was attached to a glass substrate 33 as shown in FIG. Using each of the liquid crystal displays 30 of Examples 1 to 8 and Comparative Examples 1 to 4 thus manufactured, the image contrast was evaluated by the following method. The image size of each of the liquid crystal displays 30 is, for example, 10.4 inches, and the resolution is, for example, 80.
The image contrast was evaluated as 0 × 600 dots.

The reflectance was measured using a spectrophotometer UV3100 (manufactured by Shimadzu Corporation) to measure specular reflection at 5 ° in a wavelength range of 400 to 700 nm, and expressed as a Y value corrected for visibility according to JIS Z8701. The measurement was performed in a state where the non-measurement surface was completely blackened with black magic.

Abrasion resistance is as follows. Steel wool # 0000 manufactured by Nippon Steel Wool Co., Ltd. was attached to a paperboard abrasion tester (manufactured by Kumagaya Riki Kogyo Co., Ltd.), and the antireflection film surface of the antireflection material was reciprocated 50 times with a load of 200 g. Let it. Then, the change δH (based on the following calculation) of the HAZE value of that portion was measured with a Haze meter manufactured by Toyo Seiki Co., Ltd. The larger the value of δH, the lower the wear resistance. The measurement of the HAZE value was performed using the antireflection material alone. HAZE value change δH = HAZE value after test-H before test
AZE value

The chemical resistance was measured using a cotton swab (manufactured by Johnson Corporation) impregnated with isopropyl alcohol on the antireflection film surface.
After reciprocating rubbing, the surface was evaluated as x when there was a remarkable change such as peeling or damage, as ○ when there was no change, and as △ in the middle.

The critical surface tension is determined by measuring the contact angle of the anti-reflective film of the anti-reflective material with water and methylene iodide by the Will Helmy method, as described in Basic Science of Coating (published by Yuji Harazaki, published by Maki Shoten), pages 170 to 171. Assign to expression,
From the Zismam plot, γ extrapolated to COS θ-1
It was determined from the value of the _{LV °.} COS θ = 1 + b (γ _c −γ _{LV ゜} ) where γ _{LV ゜}
≧ γ _c θ: contact angle of solid / liquid, γ _{LV ゜} : surface tension of liquid, γ _c : critical surface tension, b: constant

The stain resistance is determined by dropping one drop of rapeseed oil on the surface of the antireflection film with a dropper, and then rubbing the dropped rapeseed oil with a Bencott made by Asahi Kasei Corporation for 20 reciprocations. Further, after that, an SEM photograph of the wiped surface was taken, and it was confirmed whether or not the surface was scratched or the Bencott fibers were attached. X: when scratches or Bencot fiber adhesion is remarkably observed on the surface, x: when there is no change, and △ in the middle
And

The screen contrast is JIS C70721.
988, the contrast ratio of the liquid crystal display panel (C
R) It was evaluated according to the measuring method. FIG. 5 shows the positional relationship between the light source 60, the liquid crystal panel 61, and the photometer 62 in the evaluation of the image contrast. In this case, the distance between the light source 60 and the liquid crystal panel 61 is, for example, 1 cm, the distance between the liquid crystal panel 61 and the photometer 62 is, for example, 50 cm, and the aperture angle of the photometer is:
For example, it was set to 5 °. The light source used was 5 W EL, and the photometer used was LS-100 manufactured by Minolta Camera. The case where CR was 4 or more was evaluated as ◎, the case of 3 or more but less than 4 was evaluated as ○, the case of 2 or more and less than 3 was evaluated as Δ, and the case of less than 2 was evaluated as ×. Table 1 shows the evaluation results.

[0090]

[Table 1]

As is clear from the results shown in Table 1, the antireflection materials of the present invention all have good reflectance and durability.
While excellent properties are obtained, the antireflection material of Comparative Example has a problem in reflectance, Comparative Examples 1 to 3 have poor contrast, and Comparative Examples 1, 2 and 4 have poor abrasion resistance. Inferior, Comparative Examples 1 and 4 also have poor chemical resistance.
In Comparative Example 4, the stain resistance was not practically usable.

[0092]

As described above, according to the present invention, excellent antireflection properties are exhibited by preventing the reflection of external light such as sunlight and fluorescent lights on the display, and the image contrast is reduced. Without the need to obtain clear images without glare, optically stable, excellent abrasion resistance, chemical resistance, and an anti-reflective material and polarizing film that exhibit excellent contamination resistance Obtainable.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic cross-sectional view illustrating a configuration of an antireflection material of the present invention.

FIG. 2 is a schematic cross-sectional view showing a configuration of a polarizing film using the antireflection material of the present invention.

FIG. 3 is a schematic cross-sectional view illustrating a configuration of a liquid crystal display including a polarizing film using an antireflection material.

FIG. 4 is a schematic sectional view showing the configuration of another liquid crystal display including a polarizing film using an antireflection material.

FIG. 5 is a schematic view showing a layout of an image contrast measuring device.

[Explanation of symbols]

10 anti-reflection material, 11 transparent substrate, 12 hard coat layer, 20 polarizing film with hard coat layer, 21
Transparent substrate, 22 hard coat layer, 23 first protective material, 24 polarizing substrate, 25 second protective material, 30 liquid crystal display, 31 liquid crystal panel, 32 back light source, 33, 3
4: glass substrate, 33 ', 34': transparent electrode surface, 35:
Nematic liquid crystal, 36: polarizing film, 40: liquid crystal display, 41: liquid crystal panel, 42: back light source, 43, 44 ...
Glass substrate, 45: Nematic liquid crystal, 46, 47: Polarizing film, 60: Light source, 61: Liquid crystal panel, 62: Photometer

────────────────────────────────────────────────── ───

[Procedure amendment]

[Submission date] October 5, 1999 (1999.10.
5)

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] Claims

[Correction method] Change

[Correction contents]

[Claims]

[Procedure amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0009

[Correction method] Change

[Correction contents]

[0009]

Means for Solving the Problems (1) Contents of antireflection material The present inventors have studied the dispersibility of high refractive index ultrafine particles in the hard coat layer and the durability of the hard coat layer such as abrasion resistance. As a result of overlapping, it has been found that combining a specific compound with high refractive index ultrafine particles is extremely effective. Therefore, the antireflection material of the present invention has been made based on the above findings, and has a polymer containing a urethane (meth) acrylate compound as a polymerization component , directly or through another layer on one or both surfaces of a transparent substrate. And a hard coat layer containing at least high refractive index ultrafine particles, and an antireflection film comprising a single layer or a plurality of layers whose refractive index is adjusted is provided on the hard coat layer. Hereinafter, more preferred embodiments of the present invention will be described in detail.

[Procedure amendment 3]

[Document name to be amended] Statement

[Correction target item name] 0013

[Correction method] Change

[Correction contents]

B. Hard coat layer The hard coat referred to in the present invention is a pencil hardness test (JIS
K5400) with a hardness of H or higher. Further, the high refractive index and the low refractive index referred to in the present invention refer to the relative refractive index between adjacent layers. Next, the hard coat layer in the present invention will be described. As the resin constituting the hard coat layer of the present invention, a resin which is cured by any of radiation or heat or a combination thereof can be used, and at least contains a polymer containing a urethane (meth) acrylate compound as a polymerization component. It is essential that the refractive index of the hard coat layer and the strength of the layer are both increased.

[Procedure amendment 4]

[Document name to be amended] Statement

[Correction target item name] 0022

[Correction method] Change

[Correction contents]

At least urethane (meth) as described above
The hard coat layer is formed by curing a composition containing an acrylate compound as a polymerization component . In order to cure such a resin, for example, radiation such as ultraviolet rays, electron beams, or X-rays may be applied, but a polymerization initiator can be appropriately added as needed. As the polymerization initiator, any one can be used without particular limitation as long as it generates an active radical by heat or energy rays such as visible light and ultraviolet light. Examples of the polymerization initiator that generates an active radical by heat include 2,2′-azobis (2,4-
Examples thereof include azo compounds such as dimethylvaleronitrile) and organic peroxides such as benzoyl peroxide and lauroyl peroxide. Examples of the polymerization initiator that generates an active radical by energy rays include diethoxyacetophenone, 2-hydroxy-2-methyl-1-phenylpropan-1-one, benzyldimethylketal,
1-hydroxycyclohexyl-phenyl ketone, 2-
Acetophenones such as methyl-2-morpholino (4-thiomethylphenyl) propan-1-one; benzoin ethers such as benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether and benzoin isobutyl ether; benzophenone; o-benzoyl benzoic acid Methyl, 4-phenylbenzophenone,
4-benzoyl-4′-methyl-diphenyl sulfide, 4-benzoyl-N, N-dimethyl-N- [2-
(1-oxo-2-propenyloxy) ethyl] benzophenones such as benzenemethanaminium bromide, (4-benzoylbenzyl) trimethylammonium chloride, 2,4-diethylthioxanthone, 1-chloro-
Thioxanthones such as 4-dichlorothioxanthone,
Examples thereof include 2,4,6-trimethylbenzoyldiphenylbenzoyl oxide and a cationic polymerization initiator represented by the following chemical formula (3). These can be used alone or in combination of two or more.

[Procedure amendment 5]

[Document name to be amended] Statement

[Correction target item name] 0038

[Correction method] Change

[Correction contents]

In the present invention, a method of providing a hard coat layer on one or both sides of a transparent substrate directly or via another layer includes a urethane (meth) acrylate compound as a polymerization component and a high refractive index layer. Water or an organic solvent is mixed with the fine particles, and the mixture is dispersed with a paint shaker, sand mill, pearl mill, ball mill, attritor, roll mill, high-speed impeller disperser, jet mill, high-speed impact mill, ultrasonic disperser, etc. to paint or ink. And apply it to air doctor coating, blade coating, knife coating, reverse coating, transfer roll coating, gravure roll coating, kiss coating, cast coating, spray coating, slot orifice coating, Coating such as dark coating, electrodeposition coating, dip coating, die coating, relief printing such as flexographic printing, intaglio printing such as direct gravure printing, offset gravure printing, planographic printing such as offset printing, stencil printing such as screen printing, etc. Provided in a single layer or multiple layers on one or both sides of the transparent substrate by the printing method, when containing a solvent,
After the heat drying step, a method of curing the coating layer or the printing layer by irradiation with radiation (in the case of ultraviolet rays, a photopolymerization initiator is required) or the like may be used. When the radiation is electron beam, Cockloft-Walton type, Bande graph type, Resonant transformer type, Insulated core transformer type, Linear type,
An electron beam having an energy of 50 to 1000 KeV emitted from various electron beam accelerators such as a dynamitron type and a high frequency type is used. In the case of ultraviolet rays, an ultra-high pressure mercury lamp,
Ultraviolet rays emitted from light rays such as a high-pressure mercury lamp, a low-pressure mercury lamp, a carbon arc, a xenon arc, and a metal halide lamp can be used.

[Procedure amendment 6]

[Document name to be amended] Statement

[Correction target item name] 0076

[Correction method] Change

[Correction contents]

<Example 1> A coating liquid having the following composition was stirred with a disper for 15 minutes, and the mixed coating was applied to a transparent substrate of triacetyl cellulose (trade name: Fujitack UVD80) having a thickness of 80 µm and a transmittance of 92%. , Manufactured by Fuji Photo Film Co., Ltd., with a refractive index of 1.49), applied by a reverse coating method, dried at 100 ° C. for 2 minutes, and using one condensing high-pressure mercury lamp having an output of 120 w / cm. Ultraviolet irradiation was performed at an irradiation distance (distance from the center of the lamp to the coating surface) of 10 cm and at a processing speed (speed of the coating substrate with respect to the mercury lamp) of 5 m / min to cure the coating film. Thus, a hard coat layer having a thickness of 1.7 μm and a refractive index of 1.53 was formed. Then, a fluorine-containing silica sol (trade name: L
R201, manufactured by Nissan Chemical Industries, Ltd. (total solid content; 4
%, Solvent: ethanol / butyl cellosolve = 50/5
0, manufactured by Nissan Chemical Industries, Ltd.) on the hard coat layer by spin coating, and then applied at 100 ° C. for 1 minute.
After during drying, and 6 hours heat cured at 120 ° C., 0.1 thickness
μm, refractive index 1.38, critical surface tension 11 dyn / cm
Was formed to obtain an antireflection material of the present invention having a reflectance of 1.4%.

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Claims (4)

[Claims] 1. A hard coat layer containing at least a urethane (meth) acrylate compound and high-refractive-index ultrafine particles is provided on one or both sides of a transparent substrate, directly or via another layer. An anti-reflection material comprising a single-layer or multiple-layer anti-reflection film whose refractive index is adjusted. 2. The antireflection material according to claim 1, wherein the particle diameter of the high refractive index ultrafine particles contained in the hard coat layer is 30 nm or less. 3. The critical surface tension of the surface of the antireflection film is:
2. The composition according to claim 1, wherein the density is not more than 20 dyn / cm.
Or the antireflection material according to 2. 4. The other surface of the antireflection material according to claim 1, wherein the hard coat layer and the low refractive index layer are not provided on the transparent substrate, via a polarizing substrate. A polarizing film characterized by laminating materials.