JPH08122504A - Antireflection film and its production - Google Patents

Abstract

PURPOSE: To provide an antireflection film in which the adjustment of the refractive indices of the lower layers in direct contact with the low-refractive index layers of an antireflection sheet having the low-refractive index layers and high-refractive index layers to the refractive indices sufficient for generating an antireflection effect is facilitated, which has an excellent adhesion property to the respective layers, hardly generates crack, etc., and has excellent productivity. CONSTITUTION: The low-refractive index layers 4 which are surface layers are formed via other layers 2 on at least one surface of the front and rear surfaces of a transparent base material film 1. At least one of the other layers 2 consist of a high-refractive index layer 3 formed by bonding high-refractive index superfine particles to each other with a binder resin. The high-refractive index layer 3 is in direct contact with the low-refractive index layer 4 and the refractive index of the high-refractive index layer 3 is higher than the refractive index of the layer in contact with the surface of the high-refractive index layer 3 on the side opposite to the low-refractive index layer 4 side. The film thickness D of the high-refractive index layer 3 is expressed by the equation. In the equation, (n) is the refractive index of the high-refractive index layer 3, λ is the wavelength (380<=λ<=780nm) of visible rays, N is an integer of 0 or 1.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical lens such as a surface of a polarizing plate used in various displays such as word processors, computers and televisions, liquid crystal display devices, transparent plastic sunglasses lenses, prescription glasses lenses, camera finder lenses and the like. , Anti-reflection film that is excellent in anti-reflection of the surface of various instrument covers, window glass of automobiles, trains, etc.,
And its manufacturing method.

[0002]

2. Description of the Related Art Curve mirrors, rearview mirrors, goggles, window glasses, displays for personal computers, word processors, etc.
Other various commercial displays and the like use transparent substrates such as glass and plastic. Visual information of objects, characters, and figures is observed through these transparent substrates, or an image from a reflective layer is observed through a transparent substrate in a mirror. In this case, there is a problem that the surfaces of these transparent substrates are reflected by light and the internal visual information is difficult to see.

Conventionally, there have been the following techniques for preventing light reflection. That is, a method of applying an antireflection coating on the surface of glass or plastic, a method of providing an ultrathin film such as MgF ₂ with a film thickness of about 0.1 μm or a metal deposition film on the surface of a transparent substrate such as glass, a plastic surface such as a plastic lens. There is a method of applying an ionizing radiation curable resin on the above and forming a film of SiO ₂ or MgF ₂ thereon by vapor deposition, and a method of forming a coating film having a low refractive index on the cured film of the ionizing radiation curable resin. It was

Among the above-mentioned antireflection techniques, for example, a thin film of MgF ₂ having a thickness of about 0.1 μm formed on glass will be further described. When incident light is vertically incident on the thin film, a specific wavelength is λ ₀ , the refractive index of the antireflection film for this wavelength is n ₀ , the thickness of the antireflection film is h, and the refractive index of the substrate is _ng . Then, the antireflection film reflects the light 10 times.
It is already known that the conditions for 0% prevention and 100% light transmission must satisfy the relations of the following equations (1) and (2) (Science library physics = 9 "Optics", pp. 70-72, published by Science Inc. in 1980).

[0005]

(Equation 3) The refractive index of glass is n _g = about 1.5, the refractive index of MgF ₂ film is n ₀ = 1.38, and the wavelength of incident light λ ₀ = 5500Å
Since it is already known as (reference), when these values are substituted into the above equation (2), the thickness h of the antireflection film is about 0.1 μm.
An optical thin film around m is calculated to be optimal.

According to the above equation (1), the reflection of light is 100
%, It is understood that it is sufficient to select a material in which the refractive index of the upper coating film is approximately the square root of the refractive index of the lower coating film. It has been conventionally practiced to prevent light reflection by setting the refractive index of the coating film to a value lower than that of the underlying coating film.

Conventionally, in particular, a film-shaped polarizing element serving as a light shutter is provided on the surface of a display body such as a liquid crystal display. However, since the polarizing element itself is inferior in hardware performance, glass, A polarizing plate is formed by being protected by a transparent protective plate such as a transparent plastic plate or a transparent plastic film. However, since the transparent protective substrate itself made of a plastic such as a transparent plastic plate or a transparent plastic film is also easily scratched, in recent years, such a polarizing plate having a hard performance has been developed. As such a technique, for example, there is one described in Japanese Patent Application Laid-Open No. 1-105738.

[0008] This publication discloses a transparent protective substrate having a hard performance, that is, a triacetate film for light control, which is laminated to a polarizing element to form a polarizing plate. This film is a triacetate film having excellent hard performance by providing a cured coating film made of an ultraviolet curable epoxy acrylate resin on one surface of an unsaponified triacetate film.

[0009]

However, the above-mentioned conventional antireflection sheet imparted with the hard property has a coating film of the above ionizing radiation curable resin or thermosetting resin formed on the transparent substrate film. After curing, it was obtained by forming a low refractive index layer on it, but it is difficult to obtain a material that causes a refractive index difference between the upper layer and the lower layer in direct contact with the upper layer, so the antireflection effect is satisfactory. Was not.

In order to solve the above problems, the present invention provides an antireflection sheet obtained by forming at least a low refractive index layer and a high refractive index layer on a transparent substrate film,
The refractive index of the lower layer that is in direct contact with the low refractive index layer can be easily adjusted to a refractive index sufficient to produce the antireflection effect, excellent adhesion with each layer, and hard to cause cracks and the like. It is an object of the present invention to provide an antireflection film which is excellent in productivity.

[0011]

In order to solve the above problems, the antireflection film of the present invention comprises (1) a low refractive index layer which is a surface layer on at least one of the front and back surfaces of a transparent substrate film. And (2) at least one of the other layers is a high refractive index layer in which high refractive index ultrafine particles are bound to each other with a binder resin, The high refractive index layer is in direct contact with the low refractive index layer, and (3) the layer in which the refractive index of the high refractive index layer is in contact with the surface of the high refractive index layer opposite to the low refractive index layer side. The refractive index of the high refractive index layer is higher than that of the optical thin film, and the film thickness D of the high refractive index layer is an optical thin film represented by the following formula (3).

[0012]

[Equation 4] [N is the refractive index of the high refractive index layer, λ is the wavelength of visible light (38
0 ≤ λ ≤ 780 nm), N is an integer of 0 or 1.] Of the other layers formed of multiple layers in the antireflection film of the present invention, layers other than the high refractive index layer may be, if necessary,
An adhesive layer, a primer layer or a hard coat layer may be provided.

When the hard coat layer together with the high refractive index layer among the other layers is provided on the transparent substrate film side so as to be in contact with the high refractive index layer, the refractive index of this hard coat layer is the same as that of the transparent substrate film. Having a refractive index equal to or higher than the refractive index means that the transparent substrate film, the hard coat layer,
It is preferable because reflection at each interface between the high refractive index layers can be prevented.

The antireflection film of the present invention can form a polarizing plate by being laminated on a polarizing element. Further, the polarizing plate having such a structure can be used as a constituent element of a liquid crystal display device.

The present invention will be described in more detail. The antireflection film of the present invention includes Type I and Type II.

FIG. 1 shows an example of the layer structure of the type I antireflection film of the present invention. In FIG. 1, 1 is a transparent substrate film. Reference numeral 2 is another layer formed on the transparent substrate film, and the uppermost layer of the other layer 2 is the high refractive index layer 3 which is in direct contact with the low refractive index layer. 4 is a low refractive index layer that constitutes the outermost surface of the antireflection film of the present invention.

FIG. 2 shows an example of the layer structure of the type II antireflection film of the present invention. The type II antireflection film has an adhesive layer 5 provided between the transparent base film 1 and the other layer 2 in the type I antireflection film. Transparent substrate film : As the transparent substrate film in the antireflection film of the present invention, triacetyl cellulose film, diacetyl cellulose film, acetate butyrate cellulose film, polyether sulfone film, polyacrylic resin film, polyurethane resin film , Polyester film, polycarbonate film, polysulfone film, polyether film, trimethylpentene film, polyetherketone film, (meth) acrylonitrile film and the like can be used, but especially triacetyl cellulose film,
Further, the uniaxially stretched polyester film is preferably used because it has excellent transparency and has no optical anisotropy. The thickness thereof is preferably about 8 μm to 1000 μm.

Low Refractive Index Layer : In the antireflection film of the present invention, the low refractive index layer is formed on the transparent substrate film via other layers. The refractive index of the low refractive index layer is set to be lower than the refractive index of the high refractive index layer which is included in at least the other layers and is in direct contact with the low refractive index layer. The refractive index n _L of the low refractive index layer is, of course, in the range lower than the refractive index n _H of the high refractive index layer, but the following formula (4)

[0019]

(Equation 5) Since the antireflection effect is improved as the value becomes closer to, it is desirable to bring the condition closer to the condition of the above formula (4). The low refractive index material used for forming the low refractive index layer may be any material as long as it satisfies the above conditions, and an inorganic material or an organic material can be used.

As the low refractive index inorganic material, for example, Li
F (refractive index 1.4), MgF ₂ (refractive index 1.4), 3N
aF · AlF ₃ (refractive index 1.4), AlF ₃ (refractive index 1.4), Na ₃ AlF ₆ (cryolite, refractive index 1.3)
3), SiO _x (x: 1.50 ≦ x ≦ 2.00) (refractive index 1.35 to 1.48), and other inorganic materials are used.

A film formed of a low-refractive-index inorganic material has high hardness, and in particular, it is formed by SiO _x (x is 1.
50 ≦ x ≦ 4.00, preferably 1.70 ≦ x ≦ 2.2
It is preferable that the film of (0) formed has good hardness and excellent adhesion to the coating film of the lower layer, and can reduce heat damage to the transparent substrate film as compared with other vapor phase methods.

As the low refractive index organic material, an organic substance such as a polymer having a fluorine atom introduced therein is preferable because the refractive index thereof is as low as 1.45 or less. Polyvinylidene fluoride (refractive index n = 1.40) is mentioned as a resin that can be used as a solvent because it is easy to handle. When this polyvinylidene fluoride is used as the low refractive index organic material, the refractive index of the low refractive index layer is about 1.40,
To further lower the refractive index of the low refractive index layer, a low refractive index acrylate such as trifluoroethyl acrylate (refractive index n = 1.32) is used in an amount of 10 to 300 parts by weight, preferably 100 to 200 parts by weight. Part by weight may be added.

Since this trifluoroethyl acrylate is a monofunctional type and therefore the film strength of the low refractive index layer is not sufficient, a polyfunctional acrylate such as, for example,
It is desirable to add dipentaerythritol hexaacrylate (abbreviation: DPHA, tetrafunctional type) which is an ionizing radiation curable resin. The film strength of DPHA increases as the amount of addition increases, but from the viewpoint of reducing the refractive index of the low refractive index layer, the amount of addition is preferably small, and is 1 to 50 parts by weight, preferably 5 to 20 parts by weight. Is recommended.

When a low refractive index inorganic material is used, the low refractive index layer is formed by vapor deposition, sputtering, ion plating, using a low refractive index inorganic material on the high refractive index layer.
The coating may be formed in a single layer or a multilayer by a vapor phase method such as plasma CVD, or a composite oxide film may be formed by a sol-gel method. When a low refractive index organic material is used, a low refractive index resin composition or a low refractive index organic material containing a low refractive index inorganic material in a resin is applied to form a single-layer or multilayer coating film. Can be done by For the organic material having a low refractive index, any of a low-refractive-index thermoplastic resin such as a fluorine-based or silicone-based resin, a thermosetting resin, an ionizing radiation-curable resin, or a mixture thereof can be used. When the low refractive index layer is required to have a particularly high hardness, it is preferable to use a reaction curable resin, that is, a thermosetting resin and / or an ionizing radiation curable resin. More productivity, energy efficiency,
Considering the heat damage of the transparent substrate, it is optimal to use the ionizing radiation curable resin.

In particular, the SiO _x film having the low refractive index layer formed by the plasma CVD method has a higher density and a higher gas barrier property than an ordinary vacuum vapor deposition film. Therefore, it has an excellent moisture-proof property, and when the antireflection film of the present invention is laminated on a polarizing element for use, it has an advantage of fulfilling the moisture-proof function of the polarizing element which is considered to be weak against moisture. The thickness of the low refractive index layer is preferably a thin film of about 0.1 μm from the viewpoint of antireflection.

Other layer : Another layer is interposed between the transparent substrate film and the low refractive index layer. A layer for imparting various kinds of functionality to the antireflection film can be provided in the other layers. Of the other layers, the layer in direct contact with the low refractive index layer is essential for the purpose of the present invention to enhance the antireflection effect that the high refractive index layer has a higher refractive index than the low refractive index. Is.

Among the other layers, the layers other than the high refractive index layer may include, for example, a primer layer or an adhesive on the transparent base film for the purpose of improving the adhesiveness with the transparent base film. A layer may be provided, or a single hard coat layer or a plurality of hard coat layers may be provided to improve hard performance. As described above, the refractive index of the other layer provided between the transparent substrate film and the hard coat layer is preferably an intermediate value between the refractive index of the transparent substrate film and the refractive index of the hard coat layer.

The other layer may be formed by directly or indirectly coating on the transparent substrate film as described above, or by forming another layer on the transparent substrate film by transfer. In that case, on a layer previously formed on the transfer film,
It may be formed by coating another layer and then transferred to a transparent substrate film. Next, of the other layers, the high refractive index layer and the hard coat layer will be described in more detail.

High Refractive Index Layer : The high refractive index layer in the antireflection film of the present invention is in direct contact with the low refractive index layer and is provided on the transparent substrate film side. The refractive index of the high refractive index layer is, of course, higher than the refractive index of the low refractive index layer and the refractive index of the transparent substrate film, but on the surface opposite to the low refractive index layer side of the high refractive index layer. It is essential for the antireflection effect to be higher than the refractive index of the layer in contact.

The high-refractive-index layer is composed of high-refractive-index ultrafine particles bound together by a binder resin. This high-refractive index layer does not have high-refractive-index ultrafine particles dispersed in a resin binder, but the high-refractive-index ultrafine particles themselves are bound to each other. The refractive index of the ultrafine particles themselves can be increased.

The volume ratio of the ultrafine particles of high refractive index to the binder resin in the high refractive index layer is 0.2 to 20, and preferably 1 to 10 of ultrafine particles of high refractive index with respect to 1 part of the binder resin. It is preferable that the high refractive index ultrafine particles are bound to each other, the refractive index of the high refractive index layer is improved, and the hard performance and toughness of the coating film of the high refractive index layer are improved. If the volume ratio of the high refractive index ultrafine particles to the binder resin 1 is less than 0.2, the effect of improving the refractive index is small, and if it exceeds 20, the film forming ability is small and the hard performance and toughness are deteriorated. Therefore, neither is preferable.

The high-refractive-index ultrafine particles used in the high-refractive-index layer have a higher refractive index than the binder resin for binding the high-refractive-index ultrafine particles to each other, and a refractive index of 1.5 or more. It is desirable for adjusting the refractive index of the refractive index layer to be high. Examples of the high refractive index ultrafine particles used in the high refractive index layer include ZnO (refractive index 1.90), TiO ₂ (refractive index 2.3 to 2.7), CeO ₂ (refractive index 1.95). , Sb
₂ O ₅ (refractive index 1.71), SnO ₂ , ITO (refractive index 1.95), Y ₂ O ₃ (refractive index 1.87), La ₂ O ₃
(Refractive index 1.95), ZrO ₂ (refractive index 2.05), A
l ₂ O ₃ (refractive index 1.63) and the like.

Of these high refractive index ultrafine particles, Zn
The use of O, TiO ₂ , CeO ₂ or the like is preferable because the antireflection film of the present invention is further provided with a UV shielding effect. In addition, antimony-doped SnO
_The use of ₂ or ITO is preferable because the electron conductivity is improved, the adhesion of dust due to the antistatic effect is prevented, or the electromagnetic wave shielding effect is obtained when the antireflection film of the present invention is used for a CRT. The particle size of the high refractive index ultrafine particles is 0.1 μm or less, preferably 400 n or less in order to maintain the transparency of the high refractive index layer and obtain a sufficient light transmittance.
m or less.

The binder resin used in the high refractive index layer is a conventionally known thermoplastic resin or thermosetting resin in consideration of the hardness, adhesion, toughness of the high refractive index layer and dispersibility of the high refractive index ultrafine particles. A mold resin, an ionizing radiation curable resin or a mixture thereof can be used. In particular, when higher hardness is required, it is preferable to use a reaction curable resin, that is, a thermosetting resin and / or an ionizing radiation curable resin. For example, examples of the resin of the hard coat layer described later are used. Furthermore, considering productivity, energy efficiency, and heat damage to the transparent substrate, it is optimal to use an ionizing radiation curable resin. Further, considering the dispersibility of the high refractive index ultrafine particles, it is preferable to use an esterified polyfunctional acrylate of an acid anhydride.

The optimum film thickness D of the high refractive index layer varies depending on its refractive index and the wavelength of light for preventing reflection, but is preferably the thickness represented by the above formula (3). A specific numerical value is, for example, 50 nm although it depends on the refractive index of the high refractive index ultrafine particles and the wavelength of light for preventing reflection.
It is preferably formed of a thin film of about 250 nm.

In order to further improve the antireflection performance, it is preferable to provide a plurality of high refractive index layers. In that case, for the first high refractive index layer that is in direct contact with the low refractive index layer,
The refractive index of the second high refractive index layer formed on the side opposite to the low refractive index layer side is preferably lower than that of the first high refractive index layer in order to improve the antireflection effect. In addition, the refractive index of any high refractive index layer needs to be higher than the refractive index of the transparent substrate film.

Hard coat layer : As the binder resin that can be used in the hard coat layer contained in the other layer, any resin (for example, thermoplastic resin or thermosetting resin) can be used as long as it is transparent. , Ionizing radiation curable resins, etc.) can also be used. In order to impart hard performance, the thickness of the hard coat layer is 0.5 μm or more,
Preferably, when the thickness is 3 μm or more, the hardness can be maintained and the antireflection film can be provided with hard performance.

In the present invention, the "hard performance" or "hard coat" refers to one having a hardness of H or higher in the pencil hardness test according to JIS K5400.

In order to further improve the hardness of the hard coat layer, the binder resin used in the hard coat layer is a reaction curable resin, that is, a thermosetting resin and / or an ionizing radiation curable resin. It is preferable. The thermosetting resin, phenol resin, urea resin, diallyl phthalate resin, melamine resin, guanamine resin, unsaturated polyester resin, polyurethane resin, epoxy resin, aminoalkyd resin, melamine-urea co-condensation resin, silicon resin, poly Siloxane resin or the like is used, and if necessary, a crosslinking agent, a curing agent such as a polymerization initiator, a polymerization accelerator, a solvent, a viscosity modifier, etc. are used.

The ionizing radiation curable resin preferably has an acrylate functional group, for example, a polyester resin or polyether resin having a relatively low molecular weight,
Acrylic resin, epoxy resin, urethane resin, alkyd resin, spiro acetal resin, polybutadiene resin,
Polythiol polyene resin, oligomer or prepolymer such as (meth) acrylate of polyfunctional compound such as polyhydric alcohol, and ethyl (meth) acrylate, ethylhexyl (meth) acrylate, styrene, methylstyrene, N-vinylpyrrolidone as a reactive diluent. Monofunctional monomers such as trimethylolpropane tri (meth) acrylate, hexanediol (meth) acrylate, tripropylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, pentaerythritol tri (meth), etc. Acrylate, dipentaerythritol hexa (meth) acrylate, 1,6-hexanediol di (meth) acrylate, neopentyl glycol di (meth)
Those containing a relatively large amount of acrylate or the like can be used.

Particularly preferably, a mixture of polyester acrylate and polyurethane acrylate is used. The reason is that polyester acrylate is suitable for obtaining a hard coat because the coating is very hard, but polyester acrylate alone has a low impact resistance and becomes brittle, so that the coating has impact resistance and flexibility. Polyurethane acrylate is used together to impart the property. The mixing ratio of the polyurethane acrylate to 100 parts by weight of the polyester acrylate is 30 parts by weight or less. This is because if the value exceeds this value, the coating film becomes too soft and loses its hardness.

Further, in order to make the above ionizing radiation curable resin composition into an ultraviolet curable resin composition, acetophenones, benzophenones, Michler benzoyl benzoate, α-amyloxime are used as photopolymerization initiators therein. Ester, tetramethylthiuram monosulfide,
Thioxanthones and n-butylamine, triethylamine, tri-n-butylphosphine and the like can be mixed and used as a photosensitizer. In particular, in the present invention, it is preferable to mix urethane acrylate as an oligomer and dipentaerythritol hexa (meth) acrylate as a monomer.

In order to impart flexibility, the hard coat layer may contain 10 parts by weight or more and 100 parts by weight or less of the solvent drying type resin with respect to 100 parts by weight of the ionizing radiation curable resin. As the solvent drying type resin, a thermoplastic resin is mainly used. The type of the solvent-dried thermoplastic resin to be added to the ionizing radiation-curable resin is commonly used, but especially when a mixture of polyester acrylate and polyurethane acrylate is used for the ionizing radiation-curable resin. Polymethyl methacrylate or polybutyl methacrylate can keep the hardness of the coating film high as the solvent-drying type resin. Moreover, in this case, since the refractive index of the main ionizing radiation-curable resin is close, the transparency of the coating film is not impaired.
In particular, it is advantageous in terms of low haze value, high transmittance, and compatibility.

When a cellulosic resin such as triacetyl cellulose is used as the transparent substrate film, the solvent drying type resin contained in the ionizing radiation curable resin includes nitrocellulose, acetyl cellulose, and cellulose acetate propionate. Cellulose resins such as ethyl hydroxyethyl cellulose are advantageous in terms of adhesion and transparency of the coating film.

The reason is that when toluene is used as a solvent in the above cellulose-based resin, the transparent substrate film is used in spite of using toluene which is a non-soluble solvent of triacetyl cellulose which is a transparent substrate film. It is possible to improve the adhesion between the transparent substrate film and the coating resin even if the coating material containing this solvent-drying resin is applied to the toluene, and this toluene is triacetyl cellulose which is a transparent substrate film. This is because, since it does not dissolve, the surface of the transparent substrate film does not whiten and the transparency is maintained.

When an ionizing radiation curable resin is used as a binder resin in the hard coat layer, the curing method is a usual method for curing an ionizing radiation curable resin, that is, curing by irradiation with electron beams or ultraviolet rays. You can For example, in the case of electron beam curing, 50 to 1000 KeV emitted from various electron beam accelerators such as Cockloft-Walton type, Van de Graaff type, resonance transformer type, insulating core transformer type, linear type, dynamitron type, and high frequency type, An electron beam or the like having an energy of 100 to 300 KeV is preferably used, and in the case of ultraviolet curing, ultraviolet rays or the like emitted from light rays such as an ultrahigh pressure mercury lamp, a high pressure mercury lamp, a low pressure mercury lamp, carbon arc, xenon arc, and a metal halide lamp can be used. .

The refractive index of the hard coat layer is preferably equal to or higher than the refractive index of the transparent substrate film in order not to exceed the refractive index of the high refractive index layer in order to improve the antireflection effect. As a method for improving the refractive index of the hard coat layer, for example, in the same manner as the method for improving the refractive index of the high refractive index layer, fine particles having a high refractive index are dispersed or used, or This is achieved by introducing a component having a high refractive index as a molecule or atom constituting the resin. The ultrafine particles having a high refractive index may be the same as those used in the high refractive index layer. In addition, examples of the molecule and atom of the component that improves the refractive index include an aromatic ring, a halogen atom other than F, and atoms of S, N, and P.

Method for producing antireflection film : The method for producing the antireflection film of the present invention is to form another layer including at least a high refractive index layer and a low refractive index layer successively on a transparent substrate film. , Can be manufactured. In particular, the method of forming the high refractive index layer, the material constituting the high refractive index layer is dissolved in a suitable solvent, directly or through another layer on the transparent substrate film, coating, if necessary. The coating film is cured by heat treatment and irradiation treatment with ionizing radiation such as ultraviolet rays and electron beams.

Further, as a method for producing the antireflection film of the present invention, a transfer method using a release film is also possible. In that case, an adhesive is applied on the coated layer on the release film or on the transparent substrate film, or a layer such as a hard coat layer having adhesiveness is formed on the release film. It is necessary to keep it.

That is, the first production method of the antireflection film of the present invention is: (1) forming a high refractive index layer in which high refractive index ultrafine particles are bound to each other with a binder resin on a release film; 2) whether an adhesive is applied to either the high refractive index layer or a separately prepared transparent substrate film,
Alternatively, the hard coating agent is applied as it is or after being dissolved and dispersed in a solvent so as to have an adhesive property, and (3) the release film obtained with the coated surface facing inward is applied to the adhesive or the hard coating agent. After being laminated with the transparent base film via the release film, each layer on the release film is transferred onto the transparent base film by peeling off the release film, and (4) then transferred onto the transparent base film. The low refractive index layer is formed on the high refractive index layer which is the uppermost layer of each layer.

The second method for producing the antireflection film of the present invention is (1) forming a low refractive index layer on a release film,
Then on the low refractive index layer to form a high refractive index layer in which high refractive index ultrafine particles are mutually bound with a binder resin, on either the high refractive index layer or a separately prepared transparent substrate film, The adhesive is applied, or the hard coating agent is applied as it is or by dissolving and dispersing it in a solvent to obtain an adhesive state, and the obtained release film is applied with the coated surface inside. Alternatively, it is characterized in that each layer on the release film is transferred onto the transparent substrate film by laminating the release film after laminating with the transparent substrate film via the hard coat agent.

The third method for producing an antireflection film of the present invention is (1) forming a high refractive index layer in which high refractive index ultrafine particles are bound to each other with a binder resin on a release film,
(2) A hard coat layer is formed on the high refractive index layer, the hard coat layer is cured, and (3) the hard coat layer of the obtained release film is placed inside, and a transparent group is provided through an adhesive. (4) each layer on the release film is transferred onto the transparent base material film by laminating the release film from the laminated product, and (5) the high level transferred onto the transparent base material film. It is characterized in that a low refractive index layer is formed on the refractive index layer.

The fourth method for producing an antireflection film of the present invention is (1) forming a low refractive index layer on a release film,
(2) Next, a high refractive index layer in which high refractive index ultrafine particles are bound to each other with a binder resin is formed on the low refractive index layer,
(3) A hard coat layer is formed on the high refractive index layer, the hard coat layer is cured, and (4) the hard coat layer of the obtained release film is placed inside, and a transparent group is provided through an adhesive. It is laminated with a material film, and (5) each layer on the release film is transferred onto the transparent substrate film by peeling the release film from the laminate.

A method of manufacturing the above antireflection film will be illustrated and described in an easy-to-understand manner. The flow of the third manufacturing method of the antireflection film of the present invention is shown in FIG. 3 as an example.
In FIG. 3A, a high refractive index layer 3 in which high refractive index ultrafine particles are bound to each other by a binder resin is formed on a release film 6, and a hard coat layer is formed on the high refractive index layer 3. Shows the hard coat cured. The high refractive index layer 3 and the hard coat layer constitute another layer 2. (B)
Shows a state in which the adhesive layer 5 is formed on either the transparent substrate film 1 side or the other layer 2 side on the release film 6 and the two layers are to be laminated. (C)
The state where the release film 6 is peeled off from the laminate is shown, and (d) shows the layer structure of the antireflection film of type II of the present invention obtained by the above steps.

FIG. 4 is an example of a flow chart of the fourth manufacturing method of the antireflection film of the present invention. FIG.
In (a), a low-refractive index layer 4 is first formed on a release film 6, and then a high-refractive index layer 3 in which high-refractive-index ultrafine particles are bound to each other by a binder resin is formed. A state in which a hard coat layer is formed on the flexible layer 3 and the hard coat is cured is shown. Hereinafter, steps (b), (c) and (d) of FIG.
It is performed in the same manner as the steps (b), (c) and (d) of FIG.

The film thickness of the high refractive index layer in the antireflection film produced by the above antireflection film production method may be an optical thin film having the film thickness represented by the above formula (3). It is preferable for improving the antireflection effect.

In the antireflection film of the present invention, fine irregularities may be formed on the outermost surface thereof. Due to such unevenness, the antireflection film is provided with antiglare property and / or antireflection property. The method of forming this fine unevenness is
For example, by laminating each layer on a release film having a fine uneven surface and then laminating the release film on the transparent substrate film, fine unevenness can be imparted to the surface of the laminate.

An adhesive may be applied to the lower surface of the antireflection film of the present invention, and this antireflection film can be used by being attached to an object to be antireflection, for example, a polarizing element.

The method for producing the antireflection film of the present invention is not limited to the above-mentioned production method, and various modifications are possible. Polarizing plate and liquid crystal display device : A polarizing plate having improved antireflection properties can be obtained by laminating the antireflection film of the present invention on a polarizing element. For this polarizing element, a polyvinyl alcohol film, a polyvinyl formal film, a polyvinyl acetal film, an ethylene-vinyl acetate copolymer saponified film, which is dyed with iodine or a dye and stretched, can be used. When the base film of the antireflection film is, for example, a triacetyl cellulose film, the saponification process is performed on the triacetyl cellulose film in order to increase adhesiveness and prevent static electricity in this laminating process. This saponification treatment may be performed before or after applying the hard coat to the triacetyl cellulose film.

FIG. 5 shows an example of a polarizing plate using the antireflection film of the present invention. In the figure, an antireflection film of one example of the present invention (an antireflection film composed of a transparent substrate film / adhesive layer / another layer having a high refractive index layer / a low refractive index layer) is on a polarizing element 7. Is laminated to
On the other hand, a triacetyl cellulose film (abbreviation: TAC film) 8 is laminated on the other surface of the polarizing element 7. The antireflection film of the present invention may be laminated on both surfaces of the polarizing element 7.

FIG. 6 shows an example of a liquid crystal display device using the antireflection film of the present invention. On the liquid crystal display element 9,
The polarizing plate shown in FIG. 5, that is, a polarizing plate having a layer structure of TAC film / polarizing element / antireflection film of the present invention is laminated, and the other surface of the liquid crystal display element 9 has a TAC film / A polarizing plate having a layer structure including a polarizing element / TAC film is laminated. Note that S
In a TN type liquid crystal display device, a retardation plate is inserted between a liquid crystal display element and a polarizing plate.

[0062]

【Example】

[Example 1] A high-refractive-index layer composition having the following composition was formed on a triacetyl cellulose film (refractive index 1.40) saponified to 80 μm, which is a transparent substrate film, by a slide coating method. Coating was performed so that the thickness was about 100 nm / dry, and the solvent was removed using an oven at 100 ° C. to obtain a coating film. Using an electron beam irradiation device (Curetron: Nisshin High Voltage Co., Ltd.) for this coating film,
It was irradiated with an electron beam of 175 KV and 5 Mrad to be cured to form a high refractive index layer.

On the high refractive index layer thus obtained, a SiO ₂ film (refractive index 1.46) having a thickness of about 90 nm was formed as a low refractive index layer by a vacuum vapor deposition method to form an antireflection film. Got

(High refractive index layer composition) ZnO ultrafine particles Specific gravity 5.6 g / cm ³ (trade name: ZS
-300, manufactured by Sumitomo Cement Co., Ltd. 3.9 parts by weight Dipentaerythritol diacrylate (trade name: Kayarad DPHA, manufactured by Nippon Kayaku Co., Ltd.) 0.1 parts by weight Toluene (solvent) 96 parts by weight [Example] 2) The second embodiment corresponds to the manufacturing flow chart of the antireflection film of the present invention in FIG.

The following resin composition for a high refractive index layer was formed on a 50 μm-thick polyester film (trade name: MC-19, manufactured by Reiko Co., Ltd.) which was a release film subjected to acrylic melamine treatment. To form a high refractive index layer. Furthermore, an ionizing radiation-curable hard coat resin composition (trade name:
EXG40-9, manufactured by Dainichiseika Co., Ltd. was applied by a roll coating method at a film thickness of about 5 μm / dry, and the solvent was removed in an oven at 100 ° C. Again 175K for that coating
The hard coat layer was formed by irradiating V and 5 Mrad electron beams.

Further, a urethane-based adhesive having the composition shown below was applied by the gravure reverse method to a concentration of about 3 μm / dry, and ethyl acetate as a solvent was removed.
Triacetyl cellulose film (refractive index 1.4
9) and performed lamination. By subjecting the obtained lamination film to an aging treatment in an oven at 40 ° C. for 48 hours, and then removing the release film,
The high refractive index layer and the hard coat layer were transferred and formed on a triacetyl cellulose film. Further, a SiO ₂ film (refractive index 1.46) having a film thickness of about 90 nm was formed as a low refractive index layer on the high refractive index layer by a vacuum deposition method to obtain an antireflection film.

(Resin composition for high refractive index layer) ZnO ultrafine particles Specific gravity 5.6 g / cm ³ (trade name: ZS
-300, manufactured by Sumitomo Cement Co., Ltd. 3.9 parts by weight Polymethylmethacrylate (abbreviation: PMMA) (Brand name: BR-87, manufactured by Mitsubishi Rayon Co., Ltd.) 0.1 parts by weight Toluene 48 parts by weight Methyl ethyl ketone (abbreviation) : MEK) 48 parts by weight (urethane adhesive composition) Main agent Takelac A-310 (trade name, manufactured by Takeda Pharmaceutical Co., Ltd.) 16 parts by weight Curing agent Takenate A-3 (trade name, manufactured by Takeda Pharmaceutical Co., Ltd.) ) 4 parts by weight solvent ethyl acetate 80 parts by weight [Example 3] On a polyester film (trade name: MC-19, manufactured by Reiko Co., Ltd.) having a film thickness of 50 μm subjected to acrylic melamine treatment, which is a release film. Using the following resin compositions (I) and (II) for a high refractive index layer, two high refractive index layers were sequentially formed so that the film thickness was 150 nm and 80 nm, respectively. Furthermore, an ionizing radiation-curable hard coat resin composition (trade name: EXG40-9, Dainichiseika Co., Ltd.)
Was manufactured by a roll coating method at a film thickness of about 5 μm / dry, and the solvent was removed in an oven at 100 ° C. The coating film was irradiated again with an electron beam of 175 KV and 5 Mrad to form a hard coat layer.

Further, the urethane-based adhesive having the composition used in the above-mentioned Example 2 was applied by a gravure reverse method to about 3 μm /
After coating so as to be dry, ethyl acetate as a solvent was removed, and then a lamination was performed with a saponified triacetylcellulose film (refractive index 1.49) using a lamination roll at 40 ° C. . The obtained lamination film was subjected to aging treatment in an oven at 40 ° C. for 48 hours, and then the release film was removed to transfer and form the high refractive index layer and the hard coat layer on the triacetyl cellulose film. Further, as a low refractive index layer on the high refractive index layer, SiO _{2 is formed} by using a vacuum deposition method.
A film (refractive index 1.46) having a film thickness of about 90 nm was formed to obtain an antireflection film.

(Resin composition for high refractive index layer (I)) TiO ₂ ultrafine particles (specific gravity 4.2 g / cm ³ ) 2.9 parts by weight PMMA (trade name: BR-87, Mitsubishi Rayon Co., Ltd.)
0.1 parts by weight Toluene 97 parts by weight (resin composition for high refractive index layer (II)) ZnO ultrafine particles Specific gravity 5.6 g / cm ³ (trade name: ZS
-300, manufactured by Sumitomo Cement Co., Ltd. 3.9 parts by weight Polymethylmethacrylate (abbreviation: PMMA) (Brand name: BR-87, manufactured by Mitsubishi Rayon Co., Ltd.) 0.1 parts by weight Toluene 48 parts by weight Methyl ethyl ketone (abbreviation) : MEK) 48 parts by weight [Example 4] Example 4 is an example corresponding to the manufacturing flow chart of the antireflection film of the present invention in Fig. 6.

A release film of acrylic-melamine-treated polyester film having a thickness of 50 μm (trade name: MC-19, manufactured by Reiko Co., Ltd.) was used, and the refractive index was 1.43.
Ionizing radiation-curable fluorine-based resin (trade name: KZ, manufactured by Nippon Synthetic Rubber Co., Ltd.) [that is, a fluorine-containing resin comprising 60 parts by weight of vinylidene fluoride, 20 parts by weight of hexafluoropropylene, and 20 parts by weight of tetrafluoroethylene]. Polymer 6
While coating 40 parts by weight of dipentaerythritol hexaacrylate with 0 part by weight, an ionizing radiation-curable fluororesin composition] was applied to a film thickness of 100 nm / dry, and an electron beam was irradiated at 1 Mrad for low refraction. It was a stratum.

Then, an ionizing radiation-curable hard coat resin composition (trade name: EXG40-9, manufactured by Dainichiseika Co., Ltd.) was applied onto the low refractive index layer by a roll coating method to a film thickness of about 5 μm.
It was applied at m / dry and the solvent was removed in an oven at 100 ° C. The coating film was irradiated again with an electron beam of 175 KV and 5 Mrad to form a hard coat layer.

Further, a urethane adhesive having the composition shown below was applied by a gravure reverse method to a concentration of about 3 μm / dry, and ethyl acetate as a solvent was removed.
Triacetyl cellulose film (refractive index 1.4
9) and performed lamination. By subjecting the obtained lamination film to an aging treatment in an oven at 40 ° C. for 48 hours, and then removing the release film,
The high refractive index layer and the hard coat layer were transferred and formed on a triacetyl cellulose film to obtain the antireflection film of Example 4.

Comparative Example 1 As a transparent substrate film, a SiO ₂ film (refractive index 1.46) having a thickness of about 9 was formed on a triacetyl cellulose film having a thickness of about 80 μm by a vacuum deposition method.
The film was formed with a thickness of 0 nm to obtain an antireflection film.

Comparative Example 2 As a transparent substrate film, a TiO ₂ film (refractive index 2.3) and a SiO ₂ film (refractive index 1.46) were formed on a triacetyl cellulose film having a thickness of about 80 μm by a vacuum deposition method. 2) was formed to a thickness of 200 nm and 90 nm, respectively, to obtain an antireflection film. Regarding the above Examples 1 to 3 and Comparative Examples 1 and 2, the following Table 1 shows the measured and compared physical properties below.

Reflectivity: 5 measured by spectrophotometer
The reflectance of the antireflection film surface at 50 nm.

Pencil hardness: The test result shown in JIS K5400.

Adhesion: 10 at initial and 80 ° C., 90%
The results of the basic test after being left for 00 hours.

[0078]

[Table 1]

[0079]

The antireflection film of the present invention has an excellent antireflection property because the high refractive index layer can be an optical thin film.

Since the layer in direct contact with the low refractive index layer is the high refractive index layer formed by binding the high refractive index ultrafine particles to each other with the binder resin, the low refractive index layer and the high refractive index layer are combined. The difference in refractive index can be made sufficient, and the antireflection film of the present invention has excellent antireflection properties.

In the antireflection film of the present invention, the ratio of the high refractive index ultrafine particles constituting the high refractive index layer to the binder resin is 0.2 volume of the binder resin 1 to the high refractive index ultrafine particles. Since it is ~ 20, the high refractive index layer can have a high refractive index, and the antireflection film of the present invention has excellent antireflection properties.

[Brief description of drawings]

FIG. 1 shows an example of the layer structure of a type I antireflection film of the present invention.

FIG. 2 shows an example of the layer structure of the type II antireflection film of the present invention.

FIG. 3 is an example of a flow chart of a third method for producing an antireflection film of the present invention.

FIG. 4 is an example of a flow chart of a fourth method for producing an antireflection film of the present invention.

FIG. 5 shows an example of a polarizing plate using the antireflection film of the present invention.

FIG. 6 shows an example of a liquid crystal display device using the antireflection film of the present invention.

[Explanation of symbols]

 1 Transparent Substrate Film 2 Other Layer 3 High Refractive Index Layer 4 Low Refractive Index Layer 5 Adhesive Layer 6 Release Film 7 Polarizing Element 8 TAC Film 9 Liquid Crystal Display Element

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification number Reference number within the agency FI Technical indication location B32B 27/00 N 9349-4F (72) Inventor Hiroomi Katagiri 1-chome, Ichigaya-cho, Shinjuku-ku, Tokyo No. 1 within Dai Nippon Printing Co., Ltd. (72) Inventor, Motohiro Oka 1-1-1 Ichigayakacho, Shinjuku-ku, Tokyo Within Dai Nippon Printing Co., Ltd.

Claims (15)

[Claims] (1) A low refractive index layer as a surface layer is formed on at least one of the front and back surfaces of a transparent substrate film via another layer composed of a single layer or multiple layers, (2) At least one of the other layers is a high refractive index layer in which high refractive index ultrafine particles are bound to each other with a binder resin,
The high refractive index layer is in direct contact with the low refractive index layer, and (3) the refractive index of the high refractive index layer is in contact with the surface of the high refractive index layer opposite to the low refractive index layer side. An antireflection film having a refractive index higher than that of the layer, and a film thickness D of the high refractive index layer is an optical thin film represented by the following formula. [Equation 1] [N is the refractive index of the high refractive index layer, λ is the wavelength of visible light (38
0 ≦ λ ≦ 780 nm), N is an integer of 0 or 1] 2. The antireflection film according to claim 1, wherein the ultrafine particles having a high refractive index are higher than the refractive index of the binder resin and have a refractive index of 1.5 or more. 3. The fine particles having a high refractive index are ZnO and TiO.
₂ , Sb ₂ O ₅ , SnO ₂ , ITO, CeO ₂ , Y ₂ O
1 selected from ₃ , La ₂ O ₃ , ZrO ₂ , and Al ₂ O ₃
The antireflection film according to claim 1, which is one or more kinds of fine particles. 4. The antireflection film according to claim 1, wherein the binder resin is a thermosetting resin and / or an ionizing radiation curing resin. 5. The ratio of the ultrafine particles of high refractive index to the binder resin in the high refractive index layer is 0.2 to 20 of the ultrafine particles of high refractive index with respect to the binder resin 1 in volume ratio. The antireflection film according to 2, 3, or 4. 6. The high refractive index layer comprises a plurality of layers, and the first high refractive index layer directly contacting the low refractive index layer does not directly contact the low refractive index layer but the first high refractive index layer. The antireflection film according to claim 1, wherein the antireflection film has a higher refractive index than the second high refractive index layer that is in direct contact with the refractive index layer. 7. The layer other than the high refractive index layer among the other multilayer layers is selected from an adhesive layer, a primer layer and a hard coat layer. The antireflection film according to 5 or 6. 8. The hard coat layer is in direct contact with the high refractive index layer and has a refractive index equal to or higher than the refractive index of the transparent substrate film.
The antireflection film described. 9. The antireflection film according to claim 7, wherein the hard coat layer is made of a thermosetting resin and / or an ionizing radiation curable resin. 10. The hard coat layer has a thickness of 0.5.
The antireflection film according to claim 7, 8 or 9, wherein the hard performance of µm or more is enhanced. 11. (1) A high refractive index layer in which high refractive index ultrafine particles are bound to each other with a binder resin is formed on a release film, and (2) a transparent substrate prepared on the high refractive index layer or separately prepared. An adhesive is applied to either one of the material films, or a hard coat agent is applied as it is or by dissolving and dispersing it in a solvent to obtain an adhesive property, and (3) the obtained release After the mold film is laminated with the transparent base film through the adhesive or the hard coat agent with the coated surface inside, by peeling the release film,
Transferring each layer on the release film to the transparent substrate film, and (4) forming a low refractive index layer on the high refractive index layer which is the uppermost layer of each layer transferred on the transparent substrate film. A method for producing an antireflection film, comprising: 12. A high refractive index layer in which (1) a low refractive index layer is formed on a release film, and (2) high refractive index ultrafine particles are then bound to each other by a binder resin on the low refractive index layer. (3) Apply an adhesive to either the high refractive index layer or a separately prepared transparent substrate film, or apply the hard coating agent as it is or by dissolving and dispersing it in a solvent. (4) The release film thus obtained is laminated with a transparent base film via the adhesive or the hard coating agent, with the coated surface inside, and then the release film is formed. By peeling,
A method for producing an antireflection film, which comprises transferring each layer on a release film onto a transparent substrate film. 13. (1) A high refractive index layer in which high refractive index ultrafine particles are bound to each other by a binder resin is formed on a release film, and (2) a hard coat layer is formed on the high refractive index layer. Then, the hard coat layer is cured, and (3) the hard coat layer of the obtained release film is placed inside and laminated with a transparent substrate film via an adhesive, and (4) release from the laminate. Characteristically, each layer on the release film is transferred onto the transparent substrate film by peeling off the film, and (5) a low refractive index layer is formed on the high refractive index layer transferred onto the transparent substrate film. And a method for producing an antireflection film. 14. A high refractive index layer in which (1) a low refractive index layer is formed on a release film, and (2) high refractive index ultrafine particles are then bound to each other by a binder resin on the low refractive index layer. And (3) forming a hard coat layer on the high refractive index layer and curing the hard coat layer, and (4) setting the hard coat layer of the obtained release film on the inside and applying an adhesive. And (5) peeling the release film from the laminate to transfer each layer on the release film onto the transparent base film, thereby producing an antireflection film. Method. 15. The method for producing an antireflection film according to claim 11, 12, 13 or 14, wherein the film thickness D of the high refractive index layer constituting the antireflection film is an optical thin film represented by the following formula. A method for producing a characteristic antireflection film. [Equation 2] [N is the refractive index of the high refractive index layer, λ is the wavelength of visible light (38
0 ≦ λ ≦ 780 nm), N is an integer of 0 or 1]