WO2012157682A1

WO2012157682A1 - Method for producing antireflection film, antireflection film, polarizing plate, and image display device

Info

Publication number: WO2012157682A1
Application number: PCT/JP2012/062538
Authority: WO
Inventors: 篠原　誠司; 真理子林; 健太郎秋山
Original assignee: 大日本印刷株式会社
Priority date: 2011-05-16
Filing date: 2012-05-16
Publication date: 2012-11-22
Also published as: TW201303347A; CN103765249A; CN103765249B; KR101725585B1; KR20140037080A; JPWO2012157682A1; TWI530707B; JP6040936B2

Abstract

The present invention provides a production method for the easy production of an antireflection film which has excellent antireflection properties, excellent scratch resistance, and antifouling performance and with which the occurrence of faint whitening that has thus far not been addressed is controlled, as well as an antireflection film, and a polarizing plate and image display device that use the film. The production method for producing an antireflection film involves performing, in the following order, a step (1) for forming a coating film by applying, on a transparent substrate, a composition containing at least a fluorine-containing compound, microparticles, and a binder resin and that is for forming a low-refractive-index layer, a step (2) for phase separation of the coating film into a low-refractive-index phase and an antifouling phase, and a step (3) for forming a low-refractive-index layer and an antifouling layer for covering the entire surface of the low-refractive-index layer by heating the low-refractive-index phase and the antifouling phase, or by exposing the low-refractive-index phase and the antifouling phase to ionizing radiation. In the production method, at least a transparent substrate, a low-refractive-index layer, and an antifouling layer are formed in that order, and the fluorine atom/carbon atom ratio measured by X-ray photoelectron spectroscopy (XPS) from the antifouling layer side is between 0.6 and 1.0, the silicon atom/carbon atom ratio is less than 0.25, and the average surface roughness of the antifouling layer (Ra') is 10 nm or less.

Description

Antireflection film manufacturing method, antireflection film, polarizing plate, and image display device

The present invention relates to a method for producing an antireflection film, an antireflection film, a polarizing plate, and an image display device.

Conventionally, the surface of a display such as a liquid crystal display (LCD), a plasma display panel (PDP), or a cathode ray tube display (CRT) has a high surface hardness or a light beam irradiated from an external light source such as an incandescent lamp or a fluorescent lamp. An antireflection film is provided in order to provide an antireflection characteristic for preventing reflection. Usually, an antireflection film has a structure in which a hard coat layer and a low refractive index layer are laminated on a transparent substrate, and the low refractive index layer has a lower refractive index in order to contribute to antireflection. It is preferable that it is a rate. In addition, as a method for achieving a low reflectance, for example, a layer having a higher refractive index such as a medium refractive index layer and a high refractive index layer is formed as a thin film on the hard coat layer, and further, A method for forming the low refractive index layer is known. For example, Patent Document 1 discloses an antireflection film in which specific fine particles are contained in a refractive index control layer.

By the way, the performance required for the antireflection film is that the surface of the display as described above is scratch resistant, or is not easily soiled by fingerprints, sebum, magic, etc. Dirty is mentioned. As a method for imparting antifouling properties to an antireflection film, there is a method using an antifouling agent such as a fluorine-containing antifouling agent (for example, Patent Document 1). However, in Patent Document 1, in order to suppress a decrease in performance due to white turbidity of a composition containing an antifouling agent, the compatibility with each component in the composition is improved, that is, the weight average molecular weight is less than about 5000. It was necessary to use a low molecular weight fluorine-containing antifouling agent, and the resulting antifouling property was not sufficient.

As a method for imparting antifouling property, a specific amount of fluorine in relation to silicon element, carbon element, and fluorine element by using a fluorine-containing compound having a perfluoroalkyl group in the antifouling layer provided on the surface thereof A technique for causing atoms to exist is also proposed (for example, Patent Document 2). Although the fluorine-containing compound having a perfluoroalkyl group or the like used in Patent Document 2 is a material having excellent antifouling properties, it has poor compatibility with other materials that form an antifouling layer, such as a binder resin. It is known that when a resin composition containing the fluorine-containing compound is applied to form an antifouling layer, it is difficult to form a stable antifouling layer or whitening occurs. Sometimes it occurred.

In this respect, in Patent Document 2, since compatibility with other components is remarkably deteriorated, silicon element, carbon element, In addition, a specific amount of fluorine atoms is present in relation to fluorine element, and a certain level of compatibility is obtained to form an antifouling layer, thereby suppressing the formation of a stable antifouling layer and the occurrence of whitening (patent) Reference 2, paragraph [0039]).
In recent years, with the improvement in performance of the display as described above, the antireflection film is also required to have high performance, and in particular, the demand for whitening is increasing. Conventionally, whitening is whitening to the extent that the transparency of the film is lowered, which can be discriminated at a glance, and it has been demanded to reduce such whitening. However, in recent years, in addition to the conventional whitening, in a film that seems to have a high transparency at first glance, the slight whitening that has never been questioned so far can be visually recognized by those skilled in the art. In some cases, the surface of the coating film is not uniform and uniform and may be slightly distorted.

In addition, as a technique for imparting antifouling properties to the film, a technique for forming an antifouling layer by depositing a perfluoropolyether group-containing silane coupling agent on a transparent film substrate provided with an antireflection layer has been proposed. (For example, Patent Document 3). In the method described in Patent Document 3, the fluorine-containing compound having a perfluoroalkyl group or the like as described above generally has poor compatibility with other materials forming the antifouling layer, and the fluorine-containing compound It is difficult to form an antifouling layer by applying it as a resin composition containing an antifouling agent comprising the fluorine-containing compound using a technique called vapor deposition that can form a layer without using other materials. This is an attempt to form a layer. However, since vapor deposition is used to form the layer, other materials such as a binder resin cannot be used, and the layer strength of the antifouling layer and the adhesiveness with the transparent film substrate are deteriorated several times. The antifouling layer is peeled off from the film by wiping and the antifouling property is remarkably reduced, and further, since it is necessary to perform vapor deposition at a high temperature of several hundred degrees, the transparent film substrate shrinks due to heating, Or there existed a problem that the base material itself which had received the heat damage by high temperature vapor deposition in the accelerated deterioration test performed with respect to the product before distribution will decompose | disassemble.
The antifouling layer is generally very thin with a thickness on the order of nm, and in addition to excellent antifouling properties, it is necessary to suppress the occurrence of slight whitening, which satisfies this simultaneously. However, it has been thought that it cannot be achieved without further development while using components having compatibility with each other as components for forming the antifouling layer.

JP 2010-152111 A International Publication No. 2008/38714 Pamphlet JP 2001-188102 A

It is a schematic diagram which shows the cross section of the antireflection film of this invention. It is a schematic diagram which shows the cross section of the antireflection film of this invention. It is a schematic diagram which shows the cross section of the antireflection film of this invention. It is the shape image and phase image by the atomic force microscope of the surface of the antireflection film obtained in Example 1. It is the shape image and phase image by the atomic force microscope of the surface of the antireflection film obtained in Example 2. It is the shape image and phase image by the atomic force microscope of the surface of the antireflection film obtained in Example 3. It is the shape image and phase image by the atomic force microscope of the surface of the antireflection film obtained in Example 4. It is the shape image and phase image by the atomic force microscope of the surface of the antireflection film obtained in Example 5. It is the shape image and phase image by the atomic force microscope of the surface of the antireflection film obtained by the comparative example 1. It is the shape image and phase image by the atomic force microscope of the surface of the antireflection film obtained by the comparative example 2. It is the shape image and phase image by the atomic force microscope of the surface of the antireflection film obtained by the comparative example 3.

1. 1. Antireflection film 2. Transparent substrate Low refractive index layer 4. 4. Hard coat layer Medium refractive index layer 6. 6. High refractive index layer Middle and high refractive index layer 8. Antifouling layer

Under such circumstances, the present invention has excellent antireflection properties, excellent scratch resistance and antifouling properties, and suppresses the occurrence of subtle whitening that has never been questioned. It is an object of the present invention to provide a production method, an antireflection film, a polarizing plate and an image display device using the film, which can easily produce the antireflection film.

As a result of intensive studies to achieve the above object, the present inventors formed an antifouling layer by the method of Patent Document 2, and a cured product of the composition forming the antifouling layer was formed on the surface thereof. There may be a sea-island structure with unevenly distributed or circular or elliptical holes, and the underlying layer such as the base material is exposed, and the occurrence of this structure hinders the formation of a stable antifouling layer Furthermore, it has been found that a slight whitening that has not been questioned until now is developed. That is, although the technique disclosed in Patent Document 2 has a certain amount of fluorine atoms and obtains a certain compatibility, the ease of forming the antifouling layer is improved. Under the circumstances where high performance is required, whether or not the antifouling layer is uniformly and uniformly formed, and whether or not the sea-island structure has occurred and slight whitening has occurred There was room for consideration.
Therefore, the present inventors use a composition for forming a low refractive index layer containing a specific fluorine-containing compound containing a large number of fluorine atoms that are poorly compatible, rather than trying to improve compatibility as in the past. And by adopting a method of phase separation after applying the composition, by forming a layer so as to cover the entire surface of the film with the composition, an average surface in which the occurrence of the sea island structure as described above is suppressed It has been found that a uniform and uniform low refractive index layer having a small roughness can be obtained and the above-mentioned problems can be solved.
Furthermore, although fluorine-containing compounds with a high fluorine atom content are excellent in antifouling properties, they are poorly compatible, so it has never been considered to be used in resin compositions. Fluorine-containing compounds can be used, and extremely excellent antifouling properties can be obtained. The present invention has been completed based on such findings.

That is, the present invention
[1] It includes at least a transparent substrate, a low refractive index layer, and an antifouling layer in order, which include the following steps (1) to (3) in order, and X-ray photoelectron spectroscopy (XPS) from the antifouling layer side The fluorine atom / carbon atom ratio measured by the above is 0.6 to 1.0, the silicon atom / carbon atom ratio is less than 0.25, and the average surface roughness (Ra ′) of the antifouling layer is 10 nm. A method for producing an antireflection film,
Step (1) Step of forming a coating film by applying a composition for forming a low refractive index layer containing at least a fluorine-containing compound, fine particles and a binder resin on a transparent substrate (2) Low coating film with a low refractive index (3) Heating the low refractive index phase and the antifouling phase, or irradiating the low refractive index phase and the antifouling phase with ionizing radiation A step of forming a low refractive index layer and an antifouling layer covering the entire surface of the low refractive index layer [2] an antireflection film produced by the method of producing an antireflection film according to [1],
[3] A polarizing plate having an antireflection film on at least one surface of the polarizing film, wherein the antireflection film is the antireflection film according to [2], and [4] at least one of the antireflection film and the polarizing film. An image display device having a polarizing plate having an antireflection film on one surface on the outermost surface of the display, wherein the antireflection film is the antireflection film according to [2] above,
Is to provide.

According to the present invention, an antireflection film having excellent antireflection properties, excellent scratch resistance, and antifouling properties, and suppressing the occurrence of slight whitening that has never been questioned. Can be easily obtained, and a polarizing plate and an image display device using the antireflection film can be obtained.

[Method for producing antireflection film]
The method for producing an antireflection film of the present invention comprises a step (1) of forming a coating film by applying a composition for forming a low refractive index layer containing at least a fluorine-containing compound, fine particles and a binder resin on a transparent substrate. Step (2) Step of separating the coating film into a low refractive index phase and an antifouling phase, and Step (3) heating the low refractive index phase and the antifouling phase, or the low refractive index. A step of irradiating the phase and the antifouling phase with ionizing radiation to form a low refractive index layer and an antifouling layer covering the entire surface of the low refractive index layer in order, at least a transparent substrate, a low refractive index layer And an antifouling layer in order, the fluorine atom / carbon atom ratio measured by X-ray photoelectron spectroscopy (XPS) from the antifouling layer side is 0.6 to 1.0, and silicon atom / carbon atom The antireflection film having a ratio of less than 0.25 and an average surface roughness (Ra ′) of the antifouling layer of 10 nm or less This is a method for manufacturing a product.
The low refractive index phase and the antifouling phase formed in the step (2) are phases formed in the coating film coated with the low refractive index layer forming composition, and the binder resin in the low refractive index layer forming composition. Is in an uncured state, and the solvent preferably contained in the composition is in an evaporated state to the extent that phase separation is completed. On the other hand, these phases pass through the step (3), so that the binder resin is cured in the layer, the solvent is evaporated, and most of them are not present. Become. Therefore, in the present invention, the states present in the coating film are referred to as a low refractive index phase and an antifouling phase, and are referred to as a low refractive index layer and an antifouling layer through the step (3), respectively. In the present invention, the uncured state means a state in which the composition for forming a low refractive index layer has physical fluidity, that is, a state where viscosity can be measured, and a cured state means low refraction. It means that the composition for forming the rate layer does not have physical fluidity, that is, a state in which the viscosity cannot be measured.
Hereinafter, each step will be described.

(Process (1))
Step (1) is a coating film forming process in which a coating film is formed by applying a composition for forming a low refractive index layer containing at least a fluorine-containing compound, fine particles and a binder resin on a transparent substrate.
In the present invention, the coating film forming step preferably comprises preparing a transparent substrate, and separately preparing a composition for forming a low refractive index layer, and forming the composition for forming a low refractive index layer on the transparent substrate. This is done by applying an object.

(Preparation of composition for forming low refractive index layer)
The composition for forming a low refractive index layer is prepared by mixing homogeneously the fluorine-containing compound, fine particles, binder resin, and preferably used fluorine-containing polymer and various additives described later, and dissolving them in a solvent as necessary. Prepare.
The low refractive index forming composition is preferably in the form of a liquid dissolved in a solvent in consideration of productivity. The viscosity of the liquid composition for forming a low refractive index layer is not particularly limited as long as it is a viscosity capable of forming a coating film on the surface of the transparent substrate by a coating method described later.

(Formation of coating film)
The formation of the coating film is a gravure coat with a composition for forming a low refractive index layer prepared as described above, on the surface of the transparent substrate, so that the thickness after curing becomes a predetermined thickness described later, The coating is performed by a known method such as bar coating, roll coating, reverse roll coating, comma coating or die coating, preferably gravure coating or die coating.
Next, each component which forms a transparent base material and the composition for low-refractive-index layer formation is demonstrated.

(Transparent substrate)
The transparent substrate used in the present invention is not particularly limited as long as it is a transparent substrate generally used as a substrate for an antireflection film, but preferably a plastic film, a plastic sheet or the like is appropriately selected according to the application. Can do.

Examples of such a plastic film or plastic sheet include those made of various synthetic resins. Synthetic resins include polyethylene resins, ethylene α-olefin copolymers, polypropylene resins, polymethylpentene resins, polybutene resins, ethylene-propylene copolymers, propylene-butene copolymers, olefinic thermoplastic elastomers, or mixtures thereof. Linear or cyclic polyolefin resins such as polyethylene terephthalate resin (PET), polybutylene terephthalate resin, polyethylene naphthalate-isophthalate copolymer resin, polyester-based thermoplastic elastomer, and other polyester resins; poly (meth) acrylate methyl Resin, acrylic resin such as poly (meth) acrylic acid ethyl resin, poly (meth) butyl butyl resin; polyamide resin represented by nylon 6 or nylon 66; triacetyl cellulose Cellulose resins such as fat (TAC), diacetyl cellulose, acetate butyrate cellulose, cellophane; cyclopolyolefin resins obtained from cycloolefins such as norbornene, dicyclopentadiene, tetracyclododecene; polystyrene resins; polycarbonate resins; polyarylate resins Or a polyimide resin.

As the transparent substrate, it can be used alone or in a mixture of two or more of the above-described plastic film and plastic sheet, but from the viewpoint of mechanical strength, polyethylene terephthalate resin and acrylic resin are preferable, From the viewpoint of optical anisotropy, triacetyl cellulose resin and cyclopolyolefin are preferable.
The thickness of the transparent substrate is not particularly limited, but is usually about 5 to 1000 μm, and is preferably 15 to 80 μm and more preferably 20 to 60 μm in view of durability and handling properties.

(Composition for forming a low refractive index layer)
The composition for forming a low refractive index layer used in the present invention is a resin composition containing a fluorine-containing compound, fine particles and a binder resin. Hereinafter, each component will be described.

(Fluorine-containing compounds)
The composition for forming a low refractive index layer contains a fluorine-containing compound for the purpose of forming an antifouling layer on the antireflection film of the present invention. As the fluorine-containing compound used in the present invention, a compound having a reactive group and a perfluoropolyether group is preferable, and among them, a silane unit having a reactive group and a compound containing a silane unit having a perfluoropolyether group are preferable. Preferably mentioned. In the present invention, since the fluorine-containing compound has a reactive group, it becomes easy to bond with other components in the composition, so that it is possible to form a stronger layer, and as a result, it is thin and scratch resistant. An excellent layer is obtained. In the present invention, that the scratch resistance of the outermost surface of the antireflection film is excellent means that the outermost layer is also excellent in adhesion to the lower layer at the same time. That is, when the fluorine-containing compound in the composition for forming a low refractive index layer is present in the low refractive index phase and the antifouling phase so as to be abundant in the antifouling phase and is cured in the step (3) described later. When the reactive groups in the fluorine-containing compound contained in each phase react with each other, very excellent adhesion between the low refractive index layer and the antifouling layer can be obtained. Furthermore, the reaction between the reactive group of the fluorine-containing compound and the reactive group of the binder resin, and the curing of the binder resin itself further improve the adhesion of the antifouling layer, increase the hardness, and improve the overall resistance. It becomes a layer with excellent scratch resistance.
In addition, since the compound containing a silane unit as described above has an affinity with the fine particles contained in the low refractive index phase, when the antifouling phase is formed on the surface of the low refractive index phase, the entire surface is wetted. It is important in that a uniform and uniform antifouling layer can be obtained on the entire surface because the wettability can be maintained even when the solvent is almost evaporated from the phase. Furthermore, since such a compound is flexible, the slipperiness is improved, so that a layer having excellent scratch resistance can be obtained. And since it has affinity, wettability can be obtained stably and continuously, so that when the solvent evaporates, cissing occurs, a sea-island structure occurs, and slight whitening caused by these is suppressed. It becomes possible. Furthermore, by using a fluorine-containing compound having a silane unit and a perfluoroether group in the same molecule, phase separation between the silane unit and the perfluoropolyether is suppressed, and a more uniform and uniform surface can be obtained. It becomes easy. Here, the silane unit is a unit represented by the following general formula (1).

In the formula (1), X represents a single bond or an oxygen atom, R ¹ and R ² represent a monovalent organic group, and at least one of R ¹ and R ² represents a reactive group or a perfluoropolyether group. Is a monovalent organic group. Fluorine-containing compound used in the present invention, a silane unit is a monovalent organic group containing a silane units and R ¹ is a perfluoropolyether group is a monovalent organic radical containing, for example, R ¹ is a reactive group Or a silane unit in which R ¹ is a monovalent organic group containing a reactive group and R ² is a monovalent organic group containing a perfluoropolyether group. May be. In the plurality of silane units, R ¹ , R ² and X are independent, that is, the fluorine-containing compound of the present invention has at least a silane unit having a reactive group and a silane unit having a perfluoropolyether group. As long as it has, it may have various silane units.

In the present invention, these silane units are preferably units having a siloxane skeleton. That is, in the above formula (1), X is preferably an oxygen atom. Since the fluorine-containing compound has a siloxane skeleton, as described above, the affinity with the fine particles contained in the low refractive index layer is improved, so that the antifouling property is uniform, uniform, and has excellent antifouling properties. A layer is obtained and slight whitening hardly occurs.

The weight average molecular weight (polystyrene equivalent weight average molecular weight measured by GPC method) of the fluorine-containing compound is preferably 5,000 or more, more preferably 5,000 to 100,000, and still more preferably 5,000 to 50. , 000. If the fluorine-containing compound has a weight average molecular weight of 5,000 or more, excellent antifouling property is obtained, and if it is 100,000 or less, good solubility in an organic solvent is obtained, so that a uniform and uniform surface is obtained. It becomes easy to obtain.

Preferred examples of the reactive group include a reactive group having an ethylenically unsaturated double bond group such as a (meth) acryloyl group and a vinyl group, an epoxy group, a carboxyl group, an amino group, a hydroxyl group, and the like. However, a reactive group having an ethylenically unsaturated double bond group such as a (meth) acryloyl group or a vinyl group is preferred. When the reactive group is the above group, it easily binds to other components in the composition for forming a low refractive index layer, so that the adhesion between the low refractive index layer and the antifouling layer is stronger as described above. It is preferable because a thin layer can be formed and a thin layer having excellent scratch resistance can be obtained.

Preferred examples of the perfluoropolyether group include those represented by the following general formula (2).

In the formula (2), a to e are integers of 0 to 50, and may be the same or different. a to d are preferably integers such that the weight average molecular weight of the perfluoropolyether group represented by the formula (2) is in the range of 200 to 6000, and e is preferably 0 to 2. Xa, xb, xc, and xd are integers of 1 to 4, and may be the same or different. xa, xb, xc, and when xd is 3 and _{_{4, -C xa F 2xa, -C}} xb F 2xb, -C xc F 2xc, and -C _xd F _2xd is a by branched be linear May be.

The content of fluorine atoms in the fluorine-containing compound is preferably 5 to 80 parts by mass, more preferably 10 to 70 parts by mass, and still more preferably 20 to 60 parts by mass. When the fluorine atom content in the fluorine-containing compound is 5 parts by mass or more, excellent antifouling property is obtained, and when it is 80 parts by mass or less, good solubility in a solvent is obtained, so that it is uniform and uniform. A surface is easily obtained.

The solid content of the fluorine-containing compound is the total amount (solid) of fine particles described later in the composition for forming a low refractive index layer and a binder resin (including these when a fluorine-containing monomer and a fluorine-containing polymer are used). Min) It is preferably 5 to 30 parts by mass with respect to 100 parts by mass. In addition, although a fluorine-containing compound, microparticles | fine-particles, and binder resin are commercially available, it is common to be sold in the form contained in a solvent. In that case, the amount of these solids is the amount obtained by removing the solvent from the total amount of the commercial product. For example, the photopolymerization initiator is one of arbitrary solids contained in the composition, but is not used for calculating the content of the fluorine-containing compound.
When the content of the fluorine-containing compound is 5 parts by mass or more, the entire surface can be covered with a uniform and uniform antifouling layer with the fluorine-containing compound, so that the sea-island structure does not appear and slight whitening does not occur. . Moreover, if it is 30 parts by mass or less, the coating film surface is not flat, and the coating film surface is not rough, such as unevenness, and a uniform and uniform antifouling layer can be obtained. Excellent scratch resistance is obtained without any occurrence. That is, by setting the content of the fluorine-containing compound within the above range, an average surface roughness (Ra ′) of 10 nm or less is uniform and uniform, and a smooth antifouling layer is obtained.
For the same reason, the content of the fluorine-containing compound is more preferably 5 to 20 parts by mass, and the maximum content is more preferably 10 parts by mass. By setting the maximum content to 10 parts by mass, the average surface roughness (Ra ′) described later can be further reduced to 5 nm or less, and a smoother surface can be obtained and the scratch resistance can be improved.

(Fine particles)
The composition for forming a low refractive index layer contains fine particles. The fine particles are used for decreasing the refractive index of the layer, that is, for the purpose of improving the antireflection characteristics.
Fine particles can be used without limitation whether they are inorganic or organic. From the viewpoint of improving the antireflection properties and ensuring good surface hardness, silica fine particles and fluoro Preferred examples thereof include magnesium halide fine particles, and fine particles having a spherical shape from the point of shape and having voids themselves are preferably used. Moreover, when it has a space | gap, it is also possible to use the alumina fine particle which is normally higher refractive index than the cured film of binder resin.
Among these, silica fine particles are preferable from the viewpoint of the material in consideration of durability to wet heat. In the present invention, in order to form an antifouling layer on the entire surface of the low refractive index layer, a combination of materials forming these layers is one of the important conditions. Since the fine particles are present in a nearly densely packed state over the entire surface of the low refractive index layer, the surface properties of the low refractive index layer tend to be affected by the fine particles. The higher the affinity between the fine particles contained in the low refractive index layer and the material forming the antifouling layer, the easier the antifouling layer is formed to cover the entire surface of the low refractive index layer. This is because when the antifouling phase is phase-separated from the low refractive index phase, the antifouling phase has wettability over the entire surface of the low refractive index phase, and the wettability remains until step (3) is completed. This is because it can be held. From such a viewpoint, a combination in which the fine particles are silica fine particles made of silica and the fluorine-containing compound has a silane unit and further a siloxane unit, that is, a fluorine-containing compound containing a silica atom is particularly preferable.

Fine particles having voids themselves have fine voids on the outside and inside, and are filled with a gas such as air having a refractive index of 1.0, for example, so that the refractive index of the particles itself is low. Have. Examples of such fine particles having voids include inorganic or organic porous fine particles and hollow fine particles. For example, porous silica fine particles, hollow silica fine particles, porous polymer fine particles using acrylic resin, etc. Polymer fine particles are preferred. As the inorganic fine particles, silica fine particles having voids prepared using the technique disclosed in Japanese Patent Laid-Open No. 2001-233611 are used, and as the organic fine particles, the technique disclosed in Japanese Patent Laid-Open No. 2002-80503 is disclosed. A hollow polymer fine particle prepared by using, for example, can be mentioned as a preferred example.
Silica having voids as described above or porous silica has a refractive index of about 1.20 to 1.44, and a refractive index lower than that of general silica fine particles having a refractive index of about 1.45. Therefore, it is preferable from the viewpoint of lowering the refractive index of the low refractive index layer.

Further, as the fine particles, fine particles capable of forming a nanoporous structure in at least a part of the inside and / or the surface depending on the form, structure, aggregated state, and dispersed state in the film are also preferable.
Such fine particles are produced for the purpose of increasing the specific surface area of the above-mentioned silica fine particles, and are used for the release column for absorbing various chemical substances in the packing column and the porous portion of the surface, and for fixing the catalyst. Examples thereof include porous fine particles used, and dispersions and aggregates of hollow fine particles intended to be used for heat insulating materials and low dielectric materials. Specific examples include “Nipsil (trade name)”, “Nipgel (trade name)” manufactured by Nippon Silica Industry Co., Ltd., “Colloidal Silica UP Series (trade name)”: Nissan Chemical Industries, Ltd., and the like. .

The average primary particle size of the fine particles is preferably 5 to 200 nm, more preferably 5 to 100 nm, and even more preferably 10 to 80 nm. When the average particle diameter of the fine particles is 5 nm or more, an excellent refractive index lowering effect is obtained, and when it is 200 nm or less, the transparency of the low refractive index layer 3 is not impaired, and a good fine particle dispersion state is obtained. In the present invention, if the average particle diameter is within the above range, the fine particles may be formed in a chain. Here, the average particle diameter of the primary particles of the fine particles is obtained by observing the cross section of the antireflection film for any three visual fields using a transmission electron microscope (TEM), and arbitrary 20 particles existing in the cross section. The diameter of the particles (total of 60 particles for three fields of view) was measured on a photograph to obtain an average particle diameter.

The fine particles used in the present invention are preferably surface-treated. As the surface treatment, a surface treatment using a silane coupling agent is preferably exemplified, and among these, a surface treatment using a silane coupling agent having a (meth) acryloyl group is preferable. By subjecting the fine particles to surface treatment, the affinity with the binder resin, which will be described later, is improved, the fine particles are dispersed uniformly, and the fine particles are less likely to aggregate. Reduction, applicability of the composition for forming a low refractive index layer, and reduction in coating film strength of the composition are suppressed. In addition, when the silane coupling agent has a (meth) acryloyl group, the silane coupling agent has ionizing radiation curability, and therefore easily reacts with a binder resin described later. Therefore, the composition for forming a low refractive index layer In the coating film, fine particles are fixed to the binder resin. That is, the fine particles have a function as a crosslinking agent in the binder resin. Thereby, the tightening effect of the whole coating film is obtained, and it is possible to impart excellent surface hardness to the low refractive index layer while leaving the flexibility inherent to the binder resin. Therefore, since the low refractive index layer is deformed by utilizing its own flexibility, it has the ability to absorb and restore external impacts, so that the generation of scratches is suppressed and the surface hardness is excellent with excellent scratch resistance. It will have.

Examples of the silane coupling agent preferably used in the present invention include 3- (meth) acryloxypropyltrimethoxysilane, 3- (meth) acryloxypropyltriethoxysilane, 3- (meth) acryloxypropylmethyldimethoxysilane, 3 Examples thereof include-(meth) acryloxypropylmethyldiethoxysilane, 2- (meth) acryloxypropyltrimethoxysilane, 2- (meth) acryloxypropyltriethoxysilane and the like.

The content of fine particles in the low refractive index layer is preferably 10 to 95% by mass, more preferably 20 to 90% by mass, and further preferably 30 to 90% by mass. Here, the content of the fine particles in the low refractive index layer is the total solid content of the composition for the low refractive index layer, that is, a fluorine-containing polymer, fluorine-containing optionally used in addition to the fluorine-containing compound, fine particles, and binder resin. It is synonymous with the content of fine particles in the total amount of monomers and additives such as a polymerization initiator (total amount of all compounds other than the solvent contained in the composition). When the content of the fine particles is 10% by mass or more, the effect of using the fine particles is sufficiently obtained, and when the content is 95% or less, the average surface roughness (Ra ′) of the antifouling layer can be reduced. Since the gap between the fine particles can be satisfactorily filled with resin, excellent surface hardness can be obtained.

In the present invention, solid fine particles having no voids can be used at the same time for the purpose of improving the scratch resistance. The average primary particle size of the solid fine particles is preferably 1 to 200 nm, more preferably 1 to 100 nm, and even more preferably 5 to 20 nm. If it is 1 nm or less, the contribution to the surface hardness improvement is small, and if it is 200 nm or more, the transparency of the low refractive index layer is impaired, and it is difficult to obtain a good dispersed state of fine particles.
The content of the solid particles may be appropriately adjusted according to the scratch resistance, refractive index and the like required for the low refractive index layer. For example, the content is preferably 1 to 30% by mass and more preferably 5 to 20% by mass with respect to the total mass of the total solid content of the low refractive index layer composition.
It is desirable from the viewpoint of scratch resistance and transparency that the surface treatment is performed in the same manner as the fine particles having voids.

As the solid particles, solid particles used in conventionally known antireflection films and hard coat films can be used. Commercially available products include, for example, trade names MIBK-ST (average primary particle size: 12 nm) and MIBK-ST-ZL (average primary particle size: 88 nm) manufactured by Nissan Chemical Industries, Ltd., or JGC Catalysts & Chemicals, Inc. The product name OSCAL series (average primary particle size: 7 to 100 nm) manufactured by KK) is preferred.

(Binder resin)
The composition for forming a low refractive index layer contains a binder resin from the viewpoints of film formability and film strength. As the binder resin, the low refractive index layer is irradiated with ionizing radiation such as ultraviolet rays and electron beams into the layer of the low refractive index layer, including the above-mentioned fluorine-containing compounds and fine particles, as well as other components added as necessary. Preferred is a resin that can be fixed by being cured. In the present invention, a resin having a low compatibility with the fluorine-containing compound is used so that the above fluorine-containing compound is efficiently phase-separated to obtain an antifouling layer that completely covers the low refractive index layer. preferable.
More specifically, examples of the binder resin include thermosetting resins such as melamine, urea, epoxy, ketone, diallyl phthalate, unsaturated polyester, and phenol, or ionizing radiation curable resins. Are preferred. Among these, ionizing radiation curable resins are preferable.

The ionizing radiation curable resin refers to a resin that has an energy quantum capable of polymerizing molecules in electromagnetic waves or charged particle beams, that is, a resin that is cured by irradiation with ultraviolet rays or electron beams. Specifically, it can be appropriately selected from polymerizable monomers and polymerizable oligomers (or prepolymers) conventionally used as ionizing radiation curable resins.

As the polymerizable monomer, a (meth) acrylate monomer having a radically polymerizable unsaturated group in the molecule is preferable, and a polyfunctional (meth) acrylate monomer is particularly preferable.
The polyfunctional (meth) acrylate monomer is not particularly limited as long as it is a (meth) acrylate monomer having two or more ethylenically unsaturated bonds in the molecule. Specifically, ethylene glycol di (meth) acrylate, propylene glycol di (meth) acrylate, pentaerythritol di (meth) acrylate monostearate, dicyclopentanyl di (meth) acrylate, isocyanurate di (meth) acrylate, etc. Bifunctional (meth) acrylate; trifunctional (meth) acrylate such as trimethylolpropane tri (meth) acrylate, pentaerythritol tri (meth) acrylate, tris (acryloxyethyl) isocyanurate; pentaerythritol tetra (meth) acrylate , Dipentaerythritol tetra (meth) acrylate, dipentaerythritol penta (meth) acrylate, dipentaerythritol hexa (meth) acrylate, etc. Acrylate; the above-mentioned polyfunctional (meth) acrylate monomers of ethylene oxide-modified products, caprolactone modified products, such as propionic acid-modified products are preferably exemplified.
Among these, a trifunctional or higher functional (meth) acrylate is preferable from the viewpoint of obtaining excellent scratch resistance. These polyfunctional (meth) acrylate monomers may be used individually by 1 type, and may be used in combination of 2 or more type. More specifically, in the present invention, the desired effects such as antifouling property, scratch resistance (adhesiveness), and slight whitening prevention property can be obtained preferably by trimethylolpropane tri (meth) acrylate, pentaerythritol. Trifunctional (meth) acrylates such as tri (meth) acrylate and tris (acryloxyethyl) isocyanurate; pentaerythritol tetra (meth) acrylate, dipentaerythritol tetra (meth) acrylate, dipentaerythritol penta (meth) acrylate, A tetra- or higher functional (meth) acrylate such as dipentaerythritol hexa (meth) acrylate is preferable, and pentaerythritol tri (meth) acrylate is particularly preferable.

In the present invention, a monofunctional (meth) acrylate monomer is used in combination with the above-described polyfunctional (meth) acrylate monomer as long as the purpose of the present invention is not impaired, for the purpose of, for example, reducing the viscosity. Can do. In addition, the following polymerizable oligomers and polymers can be used for proper application adjustment by increasing the viscosity and prevention of curling due to curing shrinkage.

Next, as the polymerizable oligomer, an oligomer having a radically polymerizable unsaturated group in the molecule, for example, epoxy (meth) acrylate, urethane (meth) acrylate, polyester (meth) acrylate, polyether (meth) Examples include acrylate oligomers.

In the present invention, for example, methyl methacrylate and glycidyl methacrylate are previously polymerized to obtain a copolymer, and then obtained by condensing the glycidyl group of the copolymer with the carboxyl group of methacrylic acid or acrylic acid. It is also possible to use a reactive polymer. Such a reactive polymer is available as a commercial product, and examples of the commercial product include “macromonomer (trade name)” manufactured by Toagosei Co., Ltd.

In the present invention, an ultraviolet curable resin or an electron beam curable resin can be preferably used as the ionizing radiation curable resin.

When an ultraviolet curable resin is used as the ionizing radiation curable resin, it is preferable to add about 0.5 to 10 parts by mass of a photopolymerization initiator with respect to 100 parts by mass of the ultraviolet curable resin. The addition of 5 parts by mass is more preferable. The photopolymerization initiator can be appropriately selected from those conventionally used, and is not particularly limited. For example, for a polymerizable monomer or polymerizable oligomer having a radical polymerizable unsaturated group in the molecule. And photopolymerization initiators such as acetophenone, benzophenone, benzoin, ketal, anthraquinone, disulfide, thioxanthone, thiuram, and fluoroamine. These can be used either alone or in combination. These photopolymerization initiators are available as commercial products. For example, “Irgacure 184 (trade name)”, “Irgacure 907 (trade name)”, “Irgacure 127 (trade name)” (both Ciba Specialty Chemicals ( Etc.).

The content of the binder resin is preferably 0.5 to 20 parts by mass, more preferably 1 to 15 parts by mass with respect to 100 parts by mass of the total solid content in the composition for forming a low refractive index layer. . When the content of the binder resin is within the above range, excellent scratch resistance can be obtained, and the fluorine-containing compound can be efficiently phase separated.

(Fluoropolymer)
The composition for forming a low refractive index layer used in the present invention preferably contains a fluorine-containing polymer from the viewpoint of reducing the refractive index. Examples of the fluorine-containing polymer include (meth) acrylic acid moieties and fully fluorinated alkyl, alkenyl, aryl esters, fully or partially fluorinated vinyl ethers, fully or partially fluorinated vinyl esters, and fully or partially fluorinated vinyl ketones. Etc. are preferred.
Moreover, as a fluorine-containing polymer, what contains silicon other than a fluorine is preferable, for example, the silicone containing vinylidene fluoride copolymer which made the copolymer contain the silicone component is mentioned preferably. Examples of silicone components in this case include (poly) dimethylsiloxane, (poly) diethylsiloxane, (poly) diphenylsiloxane, (poly) methylphenylsiloxane, alkyl-modified (poly) dimethylsiloxane, azo group-containing (poly) dimethylsiloxane, , Dimethyl silicone, phenylmethyl silicone, alkyl aralkyl modified silicone, fluorosilicone, polyether modified silicone, fatty acid ester modified silicone, methyl hydrogen silicone, silanol group containing silicone, alkoxy group containing silicone, phenol group containing silicone, methacryl modified silicone, Acrylic modified silicone, amino modified silicone, carboxylic acid modified silicone, carbinol modified silicone, epoxy modified silicone, mercapto modified silicone Corn, fluorine-modified silicones, polyether-modified silicone. Of these, those having a dimethylsiloxane structure are preferred.

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

The refractive index of the fluoropolymer is preferably 1.37 to 1.45. When the refractive index is 1.37 or more, good solubility in a solvent can be obtained, and handling is easy. Moreover, the refractive index of the low-refractive-index layer to form can be reduced to a desired range as it is 1.45 or less.

Such a fluorine-containing polymer is commercially available, for example, OPSTAR TU2181-6, OPSTAR TU2181-7, OPSTAR TU2202, manufactured by JSR, OPSTAR JN35, OPSTAR TU2224, OPTOOL AR110 manufactured by Daikin Industries, Ltd., OPTOOL AR100 etc. are mentioned preferably.

The content of the fluoropolymer is preferably 1 to 30 parts by mass, more preferably 5 to 25 parts by mass with respect to 100 parts by mass of the total solid content in the composition for forming a low refractive index layer. When the content of the fluoropolymer is within the above range, the refractive index can be efficiently reduced.

(Fluorine-containing monomer)
The composition for forming a low refractive index layer used in the present invention preferably contains a fluorine-containing monomer from the viewpoint of reducing the refractive index. The fluorine-containing monomer preferably has two or more reactive functional groups in one molecule from the viewpoint of efficiently curing to form a low refractive index layer and obtaining excellent hardness. Examples of such a fluorinated monomer include a fluorinated monomer having a pentaerythritol skeleton, a fluorinated monomer having a dipentaerythritol skeleton, a fluorinated monomer having a trimethylolpropane skeleton, a fluorinated monomer having a cyclohexyl skeleton, and a linear skeleton. Preferred are fluorine-containing monomers having Among these, a compound having a pentaerythritol skeleton is preferable.

The refractive index of the fluorine-containing monomer is preferably 1.35 to 1.48, more preferably 1.37 to 1.45. When the refractive index of the fluorine-containing monomer is 1.35 or more, good solubility in a solvent can be obtained, and handling is easy. Moreover, the refractive index of the low refractive index layer to form can be reduced to a desired range as it is 1.48 or less.

Such a fluorine-containing monomer is available as a commercial product, and preferred examples include LINC series such as LINC3A having a pentaerythritol skeleton and LINC102A having a cyclohexyl skeleton manufactured by Kyoeisha Chemical Co., Ltd.

The content of the fluorine-containing monomer is preferably 1 to 30 parts by mass, more preferably 3 to 20 parts by mass with respect to 100 parts by mass of the total solid content in the composition for forming a low refractive index layer. When the content of the fluorine-containing monomer is within the above range, the refractive index can be efficiently reduced.

(Various additives)
Various additives are blended in the composition for forming a low refractive index layer used in the present invention in accordance with desired physical properties. Examples of the additive include a weather resistance improver, an abrasion resistance improver, a polymerization inhibitor, a crosslinking agent, an infrared absorber, an adhesion improver, an antioxidant, a leveling agent, a thixotropic agent, a coupling agent, and a plasticizer. Preferable examples include agents, antifoaming agents, fillers, and solvents.

(solvent)
Further, the solvent preferably used in the composition for forming a low refractive index layer is not particularly limited. For example, alcohols such as methanol, ethanol and isopropyl alcohol (IPA); ketones such as methyl ethyl ketone, methyl isobutyl ketone and cyclohexanone. Esters such as ethyl acetate and butyl acetate; halogenated hydrocarbons; aromatic hydrocarbons such as toluene and xylene; propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether Preferable examples include glycol ethers such as acetate and dipropylene glycol monoethyl ether, or mixtures thereof. Among these, ketones and glycol ethers having high affinity with fluorine-containing compounds are preferred, and particularly preferred solvents are methyl ethyl ketone, methyl isobutyl ketone, propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol monomethyl ether acetate, Propylene glycol monoethyl ether acetate. By using these alone or in combination, the dispersibility of each compound in the composition can be maintained, and the phase separation between the low refractive index phase and the antifouling phase can be preferably completed in the phase separation step (2). it can.
When a solvent other than ketones or glycol ethers is used, it is preferable to contain ketones or glycol ethers at least 50% or more, preferably 70% or more of the total solvent amount. Particularly when ketones are used, the coating property of the composition for forming a low refractive index layer is improved, and the evaporation rate of the solvent after application of the composition is moderate, so that uneven drying is less likely to occur, and the solvent is evaporated. Accordingly, the fluorine-containing compound can be efficiently phase-separated, so that a uniform and uniform large-area coating film (antifouling layer) can be easily obtained.

The amount of the solvent is appropriately adjusted so that each component can be uniformly dissolved and dispersed, and does not aggregate during storage after preparation of the composition, and does not become too dilute during application. The content of the solvent in the composition for forming a low refractive index layer is preferably 50 to 99.5% by mass, more preferably 70 to 98% by mass. By setting it as such content, the composition excellent in especially dispersion stability and suitable for long-term storage is obtained. In addition, since the solvent used for the composition for low refractive index layer formation evaporates by drying or hardening performed after apply | coating this composition, it hardly exists in a low refractive index layer.

(Process (2))
Step (2) is a step of separating the coating film formed in the above step (1) into a low refractive index phase and an antifouling phase. As a method for promoting the phase separation, for example, a heating method such as a method of heating the coating film in the air, a method of holding the coating film in steam or in an autoclave, and the like are preferable. Further, it may be simply left until phase separation without heating.
In the present invention, after the composition for forming a low refractive index layer is applied and before the binder resin in the composition is cured, the composition is heated or simply left as described above in this step. The fluorine-containing compound in the product is easily raised on the outermost surface side (the side opposite to the transparent substrate) of the coating film. As a result, in the coating film of the composition for forming a low refractive index layer, the content of the fluorine-containing compound is relatively high, and the content of the fluorine-containing compound is relatively low, and the content of the fluorine-containing compound is relatively low. Phase-separation into a low-refractive index phase that exhibits low refractive index properties, heating the antifouling phase formed on the outermost surface side, or irradiating with ionizing radiation to cover the entire surface of the low-refractive index layer By forming the fouling layer, excellent antifouling properties can be obtained. That is, in the present invention, when a coating film is formed by applying the composition for forming a low refractive index layer, it is separated into two phases in the coating film, and the coating film is divided into a low refractive index phase and an antifouling phase. And the two phases respectively form a low refractive index layer and an antifouling layer by passing through the step (3) described below, and in other words, a low refractive index layer having an antifouling layer is formed. It can be said that it forms.
The time for heating or simply leaving as described above may be about the time for the fluorine-containing compound to float on the outermost surface side of the coating film, and is usually about 1 to 30 seconds.

Also, the solvent preferably contained in the composition for forming a low refractive index layer can be evaporated by heating as described above or simply leaving it, and the solvent can be actively dried for the purpose of evaporating the solvent. In this case, the drying temperature condition is preferably in the range of 20 to 120 ° C., more preferably 40 to 100 ° C., and the drying time is preferably 10 to 180 seconds, more preferably 15 to 90 seconds. The upper limit temperature of the drying temperature is appropriately selected depending on the material of the transparent substrate to be used. On the other hand, the lower limit temperature of 20 ° C. is preferably selected from the viewpoint of forming the antifouling layer by quickly and reliably phase-separating the fluorine-containing compound to the outermost surface. Moreover, 40 degreeC or more is more preferably selected from a viewpoint of carrying out phase separation of an antifouling phase stably and forming an antifouling layer.

(Process (3))
In the step (3), the coating film after phase separation is heated, or the coating film is irradiated with ionizing radiation, and the low refractive index phase and the antifouling phase in the coating film are each formed into a low refractive index layer. And a process for making an antifouling layer. Here, the low refractive index layer is a layer having antireflection properties because fine particles are present in the layer, and the antifouling layer is a layer having antifouling properties since a fluorine-containing compound is present in the layer. It is. In this specification, for the sake of convenience, a layer containing a relatively small amount of a fluorine-containing compound has a superior antireflection property, and is therefore referred to as a low refractive index layer (low refractive index phase before heating or irradiation with ionizing radiation). The layer containing a relatively large amount of the fluorine-containing compound has a better antifouling property, and therefore is called an antifouling layer (antifouling phase before heating or irradiation with ionizing radiation).

Whether the coating film is heated or irradiated with ionizing radiation is selected depending on the binder resin contained in the composition for forming a low refractive index layer. When a thermosetting resin is employed as the binder resin, a heating process is selected. The heating conditions can be appropriately set according to the curing temperature of the thermosetting resin to be used, and can be set to 60 to 100 ° C., for example.

Moreover, what is necessary is just to irradiate an ionizing radiation to a coating film, when employ | adopting ionizing radiation curable resin as binder resin. When an electron beam is used as the ionizing radiation when curing the coating film, the acceleration voltage can be appropriately selected according to the resin used and the thickness of the layer, but the coating film is usually applied at an acceleration voltage of about 70 to 300 kV. It is preferable to cure.
In addition, in electron beam irradiation, the transmission capability increases as the acceleration voltage increases. Therefore, when using a base material that deteriorates due to the electron beam as the base material, the transmission depth of the electron beam and the thickness of the coating film are By selecting the accelerating voltage so as to be substantially equal, it is possible to suppress the irradiation of the extra electron beam to the base material, and to minimize the deterioration of the base material due to the excess electron beam.

The irradiation dose is preferably such that the crosslinking density of the curable resin in the low refractive index layer is saturated, and is usually selected in the range of 5 to 300 kGy (0.5 to 30 Mrad), preferably 10 to 50 kGy (1 to 5 Mrad). .
Further, the electron beam source is not particularly limited. For example, various electron beam accelerators such as a cockroft Walton type, a bandegraft type, a resonant transformer type, an insulated core transformer type, a linear type, a dynamitron type, and a high frequency type. Can be used.

When ultraviolet rays are used as the ionizing radiation, for example, ultraviolet rays emitted from an ultra-high pressure mercury lamp, a high-pressure mercury lamp, a low-pressure mercury lamp, a carbon arc, a xenon arc, a metal halide lamp, or the like is used. The irradiation amount of the energy ray source is preferably about 50 to 500 mJ / cm ² as an integrated exposure amount at an ultraviolet wavelength of 365 nm.

From the viewpoint of preventing oxygen inhibition on the surface of the resin composition for a low refractive index layer, the ultraviolet irradiation is preferably performed in a nitrogen atmosphere, for example, in an atmosphere having an oxygen concentration of 1000 ppm or less. In the present invention, ultraviolet irradiation is most preferable in that the low refractive index phase and the antifouling phase can be cured quickly and stably after phase separation.
The solvent is almost completely evaporated and dried by the curing in the step (3) and hardly exists in the layer. The solvent is almost evaporated in the step (2), but the solvent remaining in the layer at the end of the step (2) is considered to be almost completely evaporated in the step (3).

[Antireflection film]
The antireflection film of the present invention is obtained by the production method of the present invention, and more specifically, at least a transparent substrate, a low refractive index layer, and an antifouling layer covering the entire surface of the low refractive index layer in order. The low refractive index layer and the antifouling layer comprise a composition for forming a low refractive index layer containing a fluorine-containing compound, fine particles and a binder resin, and X-ray photoelectron spectroscopy is performed from the antifouling layer side. The fluorine atom / carbon atom ratio measured by (XPS) is 0.6 to 1.0 and the silicon atom / carbon atom ratio is less than 0.25, and the average surface roughness (Ra ′) of the antifouling layer is ) Is 10 nm or less.

The antireflection film of the present invention will be described with reference to FIGS. FIG. 1 is a schematic view showing a cross section of the antireflection film of the present invention, and FIGS. 2 and 3 are schematic views showing the cross section of a preferred layer structure of the antireflection film of the present invention as an example. An antireflection film 1 shown in FIG. 1 has a low refractive index layer 3 and an antifouling layer 8 on a transparent substrate 2. The antireflection film 1 shown in FIG. 2 has a hard coat layer 4, a medium / high refractive index layer 7, and a low refractive index layer 3 in this order on a transparent substrate 2, and the antireflection film shown in FIG. 3. The film 1 has a hard coat layer 4, a medium refractive index layer 5, a high refractive index layer 6, a low refractive index layer 3, and an antifouling layer 8 in this order on a transparent substrate 2. The layer structure of the antireflection film 1 of the present invention is not particularly limited as long as it has a low refractive index layer 3 and an antifouling layer 8 in this order on the transparent substrate 2, and for example, transparent substrate / Low refractive index layer / antifouling layer, transparent substrate / hard coat layer / low refractive index layer / antifouling layer, transparent substrate / hard coat layer / medium refractive index layer / high refractive index layer / low refractive index layer / antifouling Stain layer, transparent substrate / hard coat layer / high refractive index layer / medium refractive index layer / low refractive index layer / antifouling layer, transparent substrate / medium high refractive index layer / low refractive index layer / antifouling layer, etc. A configuration is preferred. Moreover, although not shown in figure, you may further have functional layers, such as an antistatic layer mentioned later, in the transparent base material side rather than a low refractive index layer.

(Low refractive index layer 3 and antifouling layer 8)
The low refractive index layer 3 and the antifouling layer 8 are layers formed by using a low refractive index layer forming composition containing a fluorine-containing compound, fine particles and a binder resin. These layers are formed by the above-described method for producing an antireflection film of the present invention, that is, the low refractive index layer-forming composition is applied onto a transparent substrate to form a coating film, and the coating is performed. By phase-separating the film, a low refractive index phase and an antifouling phase are formed as two phases in the coating film, and these coating films are heated or irradiated with ionizing radiation, respectively. It is a layer formed as the layer 3 and the antifouling layer 8. The content of the fluorine-containing compound contained in the low refractive index layer 3 is relatively smaller than the content of the fluorine-containing compound contained in the antifouling layer 8, and conversely the content of the fluorine-containing compound. As described above, the antifouling layer 8 having a relatively large amount becomes a layer that more strongly exhibits antifouling properties.

(Low refractive index layer 3)
The low refractive index layer 3 is most preferably a layer of N ^1/2 when the refractive index of the layer provided immediately below is N and the refractive index of air is 1, for example, When the layer immediately below the refractive index layer 3 is a hard coat layer formed using a general-purpose polyfunctional (meth) acrylic ionizing radiation curable resin, N of the hard coat layer is 1.49 to 1.53. In view of the above, 0.01 is preferably a layer having a lower N and a refractive index of 1.48 to 1.52. The lower the refractive index, the better. However, in consideration of the balance between the antireflection characteristics and the surface hardness, 1.25 to 1.45 is more preferable, and 1.25 to 1.35 is more preferable. This refractive index can be easily controlled by the type of fine particles and their content, or the amount of fluorine-containing compound used.

In order to obtain the most antireflection effect, it is preferable that the film thickness and the refractive index of the low refractive index layer 3 satisfy the relationship calculated from the following formula (I).
d _A = mλ / (4n _A ) (I)
In the formula (I), n _A represents the refractive index of the low refractive index layer, m represents a positive odd number, preferably 1 (air), λ is a wavelength, preferably in the range of 480 to 580 nm. Value. Therefore, in the present invention, the refractive index calculated from the following formula (II) where m = 1 in the above formula (I) and λ is 480 to 580 nm, which is the wavelength at which humans feel the most glare. The film thickness is preferably from the viewpoint of reducing the refractive index.
120 <n _A d _A <145 (II)
When the refractive index is in the preferred range as described above, 1.25 to 1.45, the film thickness is preferably about 80 nm to 120 nm. However, since the antireflective effect is obtained when the refractive index is lower than that of the lower layer, the film thickness may be about 120 nm to 1 μm so as to be out of this range. In the present invention, the total thickness of the low refractive index layer and the antifouling layer is preferably within the above range.

(Anti-fouling layer 8)
The antifouling layer 8 is present so as to uniformly and uniformly cover the entire surface of the low refractive index layer 3 having an average surface roughness (Ra ′) of 10 nm or less, and is antifouling to the antireflection film of the present invention. It is a layer which gives.

The average surface roughness (Ra ′) of the antifouling layer 8 is a layer of 10 nm or less, and is a uniform and uniform layer. Further, the average surface roughness (Ra ′) of the antifouling layer 8 is preferably from 0.1 to 10 nm, more preferably from 0.1 to 7 nm, and even more preferably 0 that provides the most improved scratch resistance. .1-5 nm. Here, the average surface roughness (Ra ′) is a three-dimensional extension of the centerline average roughness (Ra) defined in JIS B 0601 to the measurement surface. It is a numerical value expressed by the following equation, expressed as “average value of absolute values of deviations to the surface”. For example, the average surface roughness (Ra ′) is obtained by observing the surface shape with an atomic force microscope (AFM) and performing image analysis on the obtained image using attached analysis software (for example, SPIwin). It only has to be obtained.

As described above, the average surface roughness of the antifouling layer 8 is very small, uniform and uniform, has excellent scratch resistance and antifouling properties, and has excellent antireflection properties. It is preferable to be provided on the outermost surface of the antireflection film of the invention.

The uniform and uniform state of the antifouling layer 8 can be specifically confirmed not only by this average surface roughness (Ra ') but also by observation with an atomic force microscope (AFM). That is, when the antifouling layer 8 is observed with an atomic force microscope (AFM), the cured product of the composition for forming a low refractive index layer is not unevenly distributed in the shape image and the phase image, or is prevented by the cured product. A circular or elliptical hole is unevenly distributed in the dirty layer, and the lower layer such as a low refractive index layer or a transparent substrate is exposed, that is, it is formed over the entire surface of the antireflection film 1 without exhibiting a sea-island structure. It is in the state.

The fluorine atom / carbon atom ratio measured by X-ray photoelectron spectroscopy (XPS) from the antifouling layer 8 side is 0.6 to 1.0, and the silicon atom / carbon atom ratio is less than 0.25. Cost. Here, the fluorine atom / carbon atom ratio and silicon atom / carbon atom ratio were measured by X-ray photoelectron spectroscopy (XPS) from the antifouling layer side of the antireflection film, and the composition of fluorine atoms, carbon atoms, and silicon atoms. It is a value calculated from the ratio.
In the present invention, when the fluorine atom in the antifouling layer 8 is present at a certain level or more and the silicon atom is present at a certain level or less, that is, by using a predetermined fluorine-containing compound in a predetermined amount, an excellent antifouling property is obtained. Can be obtained, and an antireflection film that does not cause faint whitening can be obtained. In addition, since the antifouling layer is uniformly and uniformly formed on the entire surface, by having the above atomic ratio over the entire surface, better antifouling properties can be obtained and the occurrence of slight whitening can be reduced. it can.
From such a viewpoint, the fluorine atom / carbon atom ratio is more preferably 0.7 to 1.0, and the silicon atom / carbon atom ratio is more preferably 0.01 to 0.2. If the fluorine atom / carbon atom ratio is less than 0.6, the antifouling property will be insufficient. On the other hand, when it becomes larger than 1.0, handling of the agent used for achieving this, that is, the fluorine-containing compound becomes extremely difficult. In addition, when the silicon atom / carbon atom ratio is 0.25 or more, the antifouling property becomes insufficient. Therefore, in the present invention, the ratio is less than 0.25, but such a range is set. Therefore, excellent slip resistance can be expected because of improved slipperiness.

When the sea-island structure is confirmed by an atomic force microscope (AFM), or when the average surface roughness is outside the range defined by the present invention, such that a convex portion is observed in a part thereof, The atomic ratio measured by X-ray photoelectron spectroscopy (XPS) from the antifouling layer side does not fall within the range of the atomic ratio as described above. That is, in the coating film obtained by applying the composition for forming a low refractive index layer, phase separation into a low refractive index phase and an antifouling phase, and further, the antifouling layer is uniform on the low refractive index layer. The formation of a uniform layer means that the above-mentioned atomic ratio defined in the present invention is measured, and that the antifouling layer is a uniform and uniform layer is also measured by an atomic force microscope (AFM). Is to be confirmed. Therefore, the antifouling layer has an average surface roughness and an atomic ratio specified in the present invention, and in addition to excellent antifouling properties, it is possible to obtain an antireflection film that can provide scratch resistance and does not exhibit slight whitening. It can be said that. In the present invention, the average surface roughness (Ra ′) measurement by the atomic force microscope (AFM), the shape image and the phase image observation, and the atomic ratio measured by X-ray photoelectron spectroscopy (XPS) are used. It can be used as an evaluation method of whether it is an antireflection film produced by the production method of the invention or an antireflection film of the invention. Although the presence of the antifouling layer on the low refractive index layer may be observed by TEM cross-sectional observation, the above evaluation method is effective in consideration of the extremely thin layer. In addition, when the antifouling layer is formed by a vapor deposition method such as chemical vapor deposition (CVD) or physical vapor deposition (PVD), unlike the manufacturing method of the present invention, the antifouling layer and the low refractive index layer are formed of each layer. Since it does not react with the reactive group which material has, since adhesiveness is weak, scratch resistance becomes weak. That is, the difference in manufacturing method can be confirmed by the scratch resistance evaluation. Here, the scratch resistance evaluation was performed by applying a load of 300 g / cm ² or more to steel wool (Bonstar # 0000 manufactured by Nippon Steel Wool Co., Ltd.), and rubbing the surface of the antireflection film 10 times, thereby causing scratches on the surface. This is by visually checking the number.

Silicon atoms in the low refractive index layer and the antifouling layer exist in the form of SiO ₂ or C—Si—O. In the present invention, silicon atoms derived from SiO ₂ are referred to as inorganic silicon atoms, and C A silicon atom derived from —Si—O is referred to as an organosilicon atom. That is, in the present invention, the silicon atoms in the low refractive index layer and the antifouling layer have an organic silicon atom and an inorganic silicon atom.
It is considered that inorganic silicon atoms and organic silicon atoms are separated in the Si2p spectrum because of different bond energies. According to the peak separation analysis, a peak in the vicinity of 103 to 104 eV on the high bond energy side was an inorganic silicon atom, and a peak in the vicinity of 101 to 102 eV on the low bond energy side was an organosilicon atom. The silicon atom in the above silicon atom / carbon atom ratio is the total amount of inorganic silicon atoms and organic silicon atoms.
In the present invention, the organosilicon atom / carbon atom ratio measured by X-ray photoelectron spectroscopy (XPS) from the antifouling layer side is preferably 0.07 or less, more preferably 0.01 to 0.07. More preferably, it is 0.02 to 0.06. The inorganic silicon atom / carbon atom ratio is preferably 0.2 or less, more preferably 0.05 to 0.2, and still more preferably 0.08 to 0.18. When the organic silicon atom / carbon atom ratio and the inorganic silicon atom / carbon atom ratio are within the above ranges, an antireflection film that exhibits excellent scratch resistance and antifouling properties and does not cause slight whitening is obtained. Can do.

In the present invention, by satisfying the above atomic ratio, the surface of the low refractive index layer is formed using the low refractive index layer forming composition without improving the compatibility of the conventional fluorine-containing compound. By forming the antifouling layer so as to cover the whole using the method of phase separation, the antifouling layer is uniform and uniform with the average surface roughness being small and the occurrence of the sea-island structure as described above being suppressed. Become a layer.
Further, by using a composition for forming a low refractive index layer in which a fluorine-containing compound, fine particles and a binder resin are combined, not only a uniform and uniform antifouling layer 8 is obtained, but also an excellent antireflection effect as a result. It is also possible to obtain an antireflection film having characteristics, excellent scratch resistance, antifouling properties, and suppression of slight whitening.

If the surface is smooth, it is theoretically impossible for the contact angle of hexadecane to exceed 90 ° with an organic compound that forms an antifouling layer. Therefore, the contact angle and the falling angle can be measured with a commercially available contact angle meter and a falling angle meter, respectively, using hexadecane as the measurement liquid.
When the outermost surface of the antireflection film 1 of the present invention is the antifouling layer 8, the contact angle with respect to hexadecane on the surface is preferably 55 to 90 °, more preferably 60 to 90 °, and with respect to hexadecane on the surface. The sliding angle is preferably 1 to 25 °, more preferably 1 to 20 °, and the outermost surface thereof is uniform and uniform, that is, the antifouling layer 8 has a smooth structure. Since the fluorine-containing compound contained in the antifouling layer 8 covers the surface, the contact angle and the falling angle are in the above ranges, while the sea-island structure is formed to make the surface uniform and uniform. If it cannot be covered, the contact angle and the falling angle will be out of the above ranges.

The total thickness of the low refractive index layer 3 and the antifouling layer 8 varies depending on the desired refractive index, but is preferably about 80 to 120 nm as described above from the viewpoint of reducing the reflectance in the visible light region. More preferably, it is 100 to 120 nm.
It is estimated that the thickness of the antifouling layer 8 alone is in the range of 1 to 3 nm. At the time of analysis by X-ray photoelectron spectroscopy (XPS) described above, atoms contained in fine particles in the low refractive index layer are also detected, and the depth of information obtained by X-ray photoelectron spectroscopy (XPS) is 1. This is because it is reasonable to assume that the thickness is in the range of 1 to 3 nm in consideration of the thickness of 3 nm.

(Hard coat layer 4)
The antireflection film 1 of the present invention can have a hard coat layer 4 for the purpose of improving the performance of surface hardness such as scratch resistance on the antireflection film 1. Here, the hard coat refers to a performance showing a hardness of “H” or higher in a pencil hardness test specified in JIS 5600-5-4: 1999.
The hard coat layer is preferably obtained by crosslinking and curing an ionizing radiation curable resin. The ionizing radiation curable resin for forming the hard coat layer 4 is appropriately selected from the ionizing radiation curable resins used for the binder resin in the low refractive index layer forming composition described above. The photopolymerization initiator used when the ionizing radiation curable resin is an ultraviolet curable resin is also appropriately selected from those exemplified above. Various additives used in the above-described composition for forming a low refractive index layer can also be used in the same manner.

The hard coat layer 4 preferably has a film thickness after curing in the range of 0.1 to 100 μm, more preferably in the range of 0.8 to 20 μm, still more preferably in the range of 1 to 8 μm, particularly 1.5 to A range of 4 μm is preferred. If the film thickness is within the above range, sufficient hard coat performance can be obtained, and it is difficult to break against external impacts. In the present invention, the hard coat layer 4 may have a function of a medium refractive index layer 5 or a high refractive index layer 6 as described below, or may have a function of an antistatic layer. .

(Medium refractive index layer 5 and high refractive index layer 6)
The antireflection film 1 of the present invention can preferably have a medium refractive index layer 5 and a high refractive index layer 6 for the purpose of improving the antireflection performance. Here, the middle refractive index layer 5 and the high refractive index layer 6 do not need to be provided at the same time as described above as an aspect of the antireflection film 1, and for example, FIG. As shown in FIG. 1, the medium-high refractive index layer 7 may be provided as a single layer.
The refractive index of the medium refractive index layer 5, the high refractive index layer 6 or the medium high refractive index layer 7 (hereinafter sometimes referred to as these refractive index layers) is preferably in the range of 1.5 to 2.00. Can be set to That is, the middle refractive index layer 5 has a refractive index higher than at least the low refractive index layer 3 described above and lower than the high refractive index layer 6, and the refractive index is relative. . The refractive indexes of the medium refractive index layer 5 and the high refractive index layer 6 are relative as described above, but the refractive index of the medium refractive index layer 5 is usually in the range of 1.5 to 1.8. The refractive index of the refractive index layer 6 is preferably in the range of 1.6 to 2.0.

These refractive index layers can be formed of, for example, a binder resin and fine particles having a particle diameter of 100 nm or less and having a predetermined refractive index. Specific examples of such fine particles having a predetermined refractive index (the parentheses indicate the refractive index) include ZnO (1.90), TiO ₂ (2.3 to 2.7), CeO ₂ (1.95). ), Indium tin oxide (abbreviation; ITO; 1.95), antimony-doped tin oxide (abbreviation ATO; 1.80), Y ₂ O ₃ (1.87), and ZrO ₂ (2.0). Moreover, as a binder resin, it selects from the above-mentioned binder resin suitably, and is used.

The refractive index of the fine particles is preferably higher than the refractive index of the cured film of the binder resin alone. Since the refractive index of these refractive index layers is generally determined by the content of fine particles, the refractive index of the refractive index layer increases as the amount of fine particles added increases. Therefore, it is possible to form a refractive index layer having a predetermined refractive index by adjusting the addition ratio of the binder resin and the fine particles. If the fine particles have conductivity, the refractive index layer formed using such fine particles also has antistatic properties. These refractive index layers are vapor-deposited films of an inorganic oxide having a high refractive index such as titania or zirconia formed by vapor deposition methods such as chemical vapor deposition (CVD) and physical vapor deposition (PVD), or like titania. A cured resin film using a resin composition in which inorganic oxide fine particles having a high refractive index are appropriately dispersed in a binder resin can be obtained.

The film thickness of these refractive index layers is preferably in the range of 10 to 300 nm, more preferably in the range of 30 to 200 nm. The above refractive index layer (medium refractive index layer, high refractive index layer) may be provided directly on the transparent substrate 2, but the hard coat layer 4 is provided on the transparent substrate 2, and the hard coat layer 4 and the low refractive index layer are provided. 3 is preferably provided.

(Antistatic layer)
The antireflection film 1 of the present invention has an antistatic layer from the viewpoint of preventing the adhesion of dust due to the antistatic effect, or obtaining the conductivity and electromagnetic wave shielding effect when the antireflection film of the present invention is used in an image display device. Preferably. The antistatic layer is preferably provided between the transparent substrate 2 and the low refractive index layer 3. When the hard coat layer 4, medium refractive index layer 5, or high refractive index layer 6 is provided, the antistatic layer is low. It is preferable to provide the refractive index layer 3 on the outermost surface and to be in contact with the low refractive index layer 3.

It does not specifically limit as an antistatic layer, For example, what is formed with the composition for antistatic layers containing resin and an antistatic agent is mentioned preferably.
The antistatic agent is not particularly limited, and examples thereof include cationic compounds such as quaternary ammonium salts, pyridinium salts, and primary to tertiary amino groups; sulfonate groups, sulfate ester bases, phosphate ester bases, and phosphonate bases. Anionic compounds such as amino acids, aminosulfate esters, and the like; nonionic compounds such as amino alcohols, glycerol, and polyethylene glycol; organometallic compounds such as tin and titanium alkoxides; the organometallic compounds Preferred examples thereof include metal chelate compounds such as acetylacetonate salts. Compounds obtained by increasing the molecular weight of the compounds listed above can also be used.

As an antistatic agent, an organometallic compound such as a coupling agent having a tertiary amino group, a quaternary ammonium group or a metal chelate portion and having a monomer, oligomer or functional group capable of being polymerized by ionizing radiation. A polymerizable compound such as is also preferred. These antistatic agents may be ionic liquids.

Favorable examples of the antistatic agent include conductive polymers. The conductive polymer is not particularly limited. For example, aromatic conjugated poly (paraphenylene), heterocyclic conjugated polypyrrole, polythiophene, aliphatic conjugated polyacetylene, heteroatom-containing polyaniline, mixed type Conjugated poly (phenylene vinylene), a double chain conjugated system that has a plurality of conjugated chains in the molecule, and a conductive polymer that is a polymer obtained by grafting or block-copolymerizing the conjugated polymer chain to a saturated polymer. Sex complex and the like.

Preferable examples of the antistatic agent include conductive metal oxide fine particles. The conductive metal oxide fine particles are not particularly limited. For example, ZnO (refractive index: 1.90; hereinafter, all values in parentheses indicate refractive index), Sb ₂ O ₂ (1.71). , SnO ₂ (1.997), CeO ₂ (1.95), indium tin oxide (abbreviation: ITO; 1.95), In ₂ O ₃ (2.00), Al ₂ O ₃ (1.63), antimony Examples include doped tin oxide (abbreviation ATO; 2.0) and aluminum-doped zinc oxide (abbreviation AZO; 2.0).

As the content of the antistatic agent in the composition for antistatic layer, the effect of containing the antistatic agent can be fully enjoyed, and the effect obtained in the optical laminate produced by the present invention described above can be obtained. It is preferable to blend appropriately within a range that does not inhibit.
The resin used in the antistatic layer, that is, the resin used in the composition for the antistatic layer is not particularly limited. For example, ionizing radiation that is a resin curable by ultraviolet rays or electron beams similar to the resin described in the hard coat layer described above. Examples thereof include a curable resin, a mixture of an ionizing radiation curable resin and a solvent-drying resin, or a thermosetting resin.
The antistatic layer is formed by coating the antistatic layer composition prepared using each of the above-described materials on the light-transmitting base material, etc. It can be formed by curing by irradiation or heating.

[Polarizer]
The polarizing plate of the present invention has an antireflection film on at least one surface of the polarizing film, and the antireflection film is obtained by the production method of the present invention, that is, at least a transparent substrate, a low refractive index layer, And an antifouling layer covering the entire surface of the low refractive index layer in order, wherein the low refractive index layer and the antifouling layer contain a fluorine-containing compound, fine particles and a binder resin. The fluorine atom / carbon atom ratio measured by X-ray photoelectron spectroscopy (XPS) from the antifouling layer side is 0.6 to 1.0, and the silicon atom / carbon atom ratio is less than 0.25. The average surface roughness (Ra ′) of the antifouling layer is 10 nm or less. With such a configuration, the polarizing plate of the present invention has an antireflection function excellent in physical strength and light resistance, and can greatly reduce the cost and thin the display device.

Usually, the polarizing plate is provided with protective films on both sides of the polarizing film, but the polarizing plate of the present invention is provided with the antireflection film of the present invention on at least one of them. In the present invention, the antireflection film of the present invention can be provided on one surface or both surfaces of the polarizing film. When provided on one surface, from the viewpoint of improving the viewing angle characteristics of the liquid crystal display screen, an optical compensation film (retardation film) having an optical compensation layer including an optically anisotropic layer on the other surface is preferable. .

When using the antireflection film of the present invention as a protective film, it is particularly preferable to use a triacetyl cellulose film as the transparent support. In this case, the transparent support of the protective film using the antireflection film is preferably adhered to the polarizing film through an adhesive layer made of polyvinyl alcohol, if necessary. Further, as described above, a structure having a protective film, preferably the above-described optical compensation film (retardation film) on the other side of the polarizing film is preferable. You may have an adhesive layer in the surface on the opposite side to the polarizing film of the other protective film. By setting it as such a structure, the polarizing plate of this invention can improve the contrast in the bright room of a liquid crystal display device, and the viewing angle of up and down, right and left.

[Image display device]
The image display device of the present invention has an antireflection film or a polarizing plate having an antireflection film on at least one side of a polarizing film on the outermost surface of the display, and the antireflection film is obtained by the production method of the present invention. In other words, at least a transparent substrate, a low refractive index layer, and an antifouling layer covering the entire surface of the low refractive index layer are sequentially provided, and the low refractive index layer and the antifouling layer comprise a fluorine-containing compound and fine particles. And a fluorine atom / carbon atom ratio measured by X-ray photoelectron spectroscopy (XPS) from the antifouling layer side from 0.6 to 1.0. And the silicon atom / carbon atom ratio is less than 0.25, and the average surface roughness (Ra ′) of the antifouling layer is 10 nm or less.
Examples of the display include a liquid crystal display (LCD), a plasma display panel (PDP), a cathode ray tube display (CRT), an inorganic and organic electroluminescence display, a rear projection display, a fluorescent display tube (VFD), a touch panel, and a mobile PC. Preferable examples include displays such as electronic paper. Moreover, as an image display apparatus, the apparatus provided with these displays, for example, a personal computer, a portable information terminal, a game machine, a digital camera, a digital video camera etc. are mentioned preferably.

Next, the present invention will be described in more detail with reference to examples. However, the present invention is not limited to the examples.

(Evaluation methods)
1. Minimum reflectance (evaluation of antireflection characteristics)
About the antireflection film obtained in each of Examples and Comparative Examples, a black tape for preventing back reflection of the film is attached to the side of the transparent base material where the low refractive index layer is not provided, and from the surface of the low refractive index layer. The reflectance is measured using a spectrophotometer (“UV-2550 (model number)” manufactured by Shimadzu Corporation) equipped with a 5 ° specular reflection measuring device, and the minimum value in the wavelength range of 380 to 780 nm is the lowest. The reflectance was used. It shows that an antireflection film has the outstanding antireflection property, so that the minimum reflectance is small.
2. Evaluation of coated surface A black tape is applied to the surface of the film on which the low refractive index layer is not formed, and the surface on which the low refractive index layer is formed is visually observed with a three-wavelength lamp. Evaluated.
○: The surface of the low refractive index layer was uniform and uniform.
Δ: A slight distortion was observed on the surface of the low refractive index layer as compared with the above evaluation of ○.
X: The surface of the low refractive index layer was slightly white.
3. Evaluation of surface scratch resistance and adhesion The antireflection film obtained in each example and comparative example was subjected to 10 reciprocations by applying a load of 300 g / cm ² to steel wool (Bonstar # 0000, manufactured by Nippon Steel Wool Co., Ltd.). The result of rubbing and visual observation was evaluated according to the following criteria. The smaller the scratches, the better the scratch resistance and the adhesion between the low refractive index layer and the antifouling layer.
○: No scratch was found Δ: The number of scratches was 1 to 5 ×: The number of scratches was 6 or more Evaluation of antifouling property (1) Antifouling property against fingerprints After attaching a fingerprint to the surface of the antireflection film obtained in each of Examples and Comparative Examples, wiping with Bencott M-3 (manufactured by Asahi Kasei Corporation) Ease of wiping was visually confirmed and evaluated according to the following criteria.
○: Fingerprints were easily wiped off △: Fingerprints were wiped off ×: Fingerprints were not wiped away (2) The state when drawn with oily magic on the surface of the antireflection film obtained in each Example and Comparative Example The condition after wiping with a cloth was visually confirmed and evaluated according to the following criteria.
A: The ink was repelled in a spherical shape and was easy to wipe off. ○: The ink was repelled and the line was thinned, so that it was easy to wipe off. Measurement of atomic ratio of low refractive index layer by X-ray photoelectron spectroscopy The surface (antifouling layer) of the antireflection film obtained in each Example and Comparative Example was analyzed by X-ray photoelectron spectroscopy (XPS), and a fluorine-containing compound The atomic ratio, which is an index of how much phase separation occurs to form an antifouling layer, was obtained by the following method.
The apparatus used is an XPS apparatus (“ESCALAB 220i-XL (model number)”, manufactured by Thermo Fisher Scientific), X-ray output: 10 kV · 16 mA (160 W), lens: Large Area XL (magnetic lens), aperture Opening angle: F.F. O. V. = Open, A. A. = Open, measurement area: 700 μmφ, photoelectron capture angle: 90 degrees (with input lens on the sample normal), charge neutralization: electron neutralization gun +4 (V) · 0.08 (mA), for neutralization assistance Analysis was performed using a metal mask. Using the atomic composition of carbon atoms, nitrogen atoms, oxygen atoms, fluorine atoms and silicon atoms on the surface of the antireflection film obtained by this measurement, the fluorine atom / carbon atom ratio and the silicon atom / carbon atom ratio were determined. Calculated. Further, with respect to silicon atoms, an inorganic silicon component (SiO ₂ ) in which a peak is detected in the vicinity of 103 to 104 eV and an organic silicon component (C—) in which a peak is detected in the vicinity of 101 to 102 eV by peak separation analysis of the Si2p spectrum. The atomic composition was measured separately for Si—O), and the inorganic silicon atom / carbon atom ratio and the organic silicon atom / carbon atom ratio were calculated.
6). Evaluation of surface condition (measurement of contact angle and sliding angle)
For the antireflection films obtained in each of Examples and Comparative Examples, hexadecane was used as the measurement liquid, and the contact angle and the tumbling angle were measured using a measuring instrument (“DM-500 (model number)”, manufactured by Kyowa Interface Science Co., Ltd.). Was measured. The droplet volume was 2 μl.
7. Evaluation of surface condition (Evaluation of surface observation by atomic force microscope)
The surface of the antireflection film obtained in each example and comparative example was subjected to dynamic force mode using an atomic force microscope (AFM) (“L-trace (model number)”, manufactured by SII Nanotechnology Co., Ltd.). Shape images and phase images were observed at a scanning frequency of 0.4 to 1.0 Hz and a scanning range of 3 μm. As the cantilever, “OMCL-AC160TS-C2 (model number)” (manufactured by KS Olympus Corporation, spring constant: 42 N / m) was used. Here, the cantilever used for observation was always a new cantilever so as not to reduce the resolution due to probe contamination. Further, in order to prevent wear deterioration during observation, it was performed under the condition that the load applied to the probe is as small as possible without sacrificing the resolution, and observation was performed with a resolution of 512 pixels × 256 pixels. After observation, the inclination of the data was corrected with the attached software.
By this surface observation, when the antifouling layer is formed by phase separation on the entire surface of the low refractive index layer, a uniform and uniform state can be confirmed, while on the other hand, the antifouling layer is phase separated on the entire surface. In the case where no is formed, the surface can be confirmed as a sea-island pattern of unevenness due to the phase-separated portion and the non-phase-separated portion. Here, if it is uniform and uniform, it can be said that there is no slight whitening or roughening of the coated surface even when visually observed, and the low refractive index layer and the antifouling layer are well formed.
○: The antifouling layer was uniform and uniform. Δ: The antifouling layer did not have a sea-island structure, but a slight distortion was observed when compared with the evaluation of the above ○.
X: The antifouling layer has a sea-island structure, and slight whitening and roughening of the coated surface were visually observed. Measurement of average surface roughness (Ra ') Surface shape is observed with the above atomic force microscope (AFM), and image analysis is performed using analysis software (SPIwin) to obtain average surface roughness (Ra'). It was.

Preparation Example 1: Preparation of Composition 1 for Forming Low Refractive Index Layer Components of the following composition were mixed at the following mass ratio to prepare Composition 1 for forming a low refractive index layer.
Composition 1 for forming a low refractive index layer
Pentaerythritol triacrylate (PETA): 0.10 parts by mass Fluorine-containing compound ^{* 1} : 1.23 parts by mass Hollow silica particle dispersion ^{* 2} : 6.69 parts by mass Solid silica particle dispersion ^{* 3} : 0.74 parts by mass Part Fluoropolymer ^{* 4} : 2.79 parts by mass Fluorine monomer ^{* 5} : 2.23 parts by mass Photopolymerization initiator ^{* 6} : 0.08 parts by mass Methyl isobutyl ketone: 57.03 parts by mass Propylene glycol monomethyl ether acetate: 29.1 parts by mass * 1, “X-71-1203M (trade name)” manufactured by Shin-Etsu Chemical Co., Ltd., 20% by mass solution (solvent: methyl isobutyl ketone, photocurable reactive group: (meth) acryloyl group, reaction Fluorine-containing compound having a silane unit having a property and a silane unit having a perfluoropolyether group)
* 2. The content of hollow silica particles in the dispersion is 20% by mass, and the content of solvent (methyl isobutyl ketone) is 80% by mass. Moreover, the average particle diameter of hollow silica particles is 60 nm, and has a photocurable reactive group by surface treatment.
* 3, “MIBK-SD (trade name)”, average primary particle size: 12 nm, solid content: 30% by mass, solvent: methyl isobutyl ketone, solid silica particles are methacryloyl which is a photo-curable reactive group by surface treatment. Has a group.
* 4, “OPSTAR JN35 (trade name)”, manufactured by JSR, 20% by mass solution (solvent: methyl isobutyl ketone)
* 5, “LINC3A (trade name)”: manufactured by Kyoeisha Chemical Co., Ltd., fluorine-containing monomer having a pentaerythritol skeleton, 20% by mass solution (solvent: methyl isobutyl ketone)
* 6, “Irgacure 127 (trade name)” manufactured by Ciba Specialty Chemicals Co., Ltd.

Preparation Example 2: Preparation of hard coat layer forming composition 1 The components of the following composition were mixed at the following mass ratio to prepare hard coat layer forming composition 1.
Hard coat layer forming composition 1
Urethane acrylate ^{* 7} : 15 parts by weight Isocyanuric acid EO-modified triacrylate ^{* 8} : 15 parts by weight Polymerization initiator ^{* 9} : 2 parts by weight Methyl ethyl ketone: 70 parts by weight * 7, “UV1700B (trade name)”, Nippon Synthetic Chemical Co., Ltd. * 8, "M315 (trade name)", Toagosei Co., Ltd. * 9, "Irgacure 184 (trade name)": Ciba Specialty Chemicals

Example 1
A hard coat layer-forming composition 1 is bar-coated on a triacetylcellulose (TAC) resin film having a thickness of 80 μm, dried at 50 ° C. for 1 minute, and after removing the solvent, an ultraviolet irradiation device (fusion UV) Using a light source H bulb manufactured by System Japan Co., Ltd., it was cured by irradiation with ultraviolet rays at an irradiation dose of 30 mJ / cm ² to obtain a hard coat layer having a thickness of about 10 μm.
Next, on the obtained hard coat layer, the low refractive index layer-forming composition 1 prepared in Preparation Example 1 is bar-coated to form a coating film (step (1)) at 50 ° C. for 1 minute. After the heat treatment is performed, the coating film is phase-separated into a low refractive index phase and an antifouling phase, and after removing the solvent (step (2)), it is cured by irradiation with ultraviolet rays at an irradiation dose of 200 mJ / cm ² , A low refractive index layer and an antifouling layer were formed (step (3)) to obtain an antireflection film having a transparent substrate, a hard coat layer, a low refractive index layer, and an antifouling layer. During the curing, the solvent was almost completely evaporated, and the total thickness of the low refractive index layer and the antifouling layer was about 100 nm. Further, when the atomic ratio was measured by X-ray photoelectron spectroscopy (XPS), atoms contained in the fine particles in the low refractive index layer were also detected. Considering that the thickness of the X-ray photoelectron spectroscopy (XPS) antifouling layer is 1 to 3 nm, the thickness of the obtained antifouling layer is estimated to be in the range of 1 to 3 nm.
Table 1 shows the results of evaluation of the obtained antireflection film by the above evaluation method. An atomic force microscope (shape image and phase image) is shown in FIG.

Example 2
In Example 1, an antireflection film was obtained in the same manner as in Example 1 except that the composition 1 for forming a low refractive index layer was replaced with the composition 2 for forming a low refractive index layer described below. Table 1 shows the results of evaluation of the obtained antireflection film by the above evaluation method. Further, an atomic force microscope image (shape image and phase image) is shown in FIG.

Composition 2 for forming a low refractive index layer
Pentaerythritol triacrylate (PETA): 1.32 parts by mass Fluorine-containing compound ^{* 1} : 1.32 parts by mass Hollow silica particle dispersion ^{* 2} : 6.61 parts by mass Photopolymerization initiator ^{* 6} : 0.07 parts by mass Methyl Isobutyl ketone: 61.03 parts by mass Propylene glycol monomethyl ether acetate: 29.1 parts by mass

Example 3
In Example 1, an antireflection film was obtained in the same manner as in Example 1 except that the composition 1 for forming a low refractive index layer was replaced with the composition 3 for forming a low refractive index layer described below. Table 1 shows the results of evaluation of the obtained antireflection film by the above evaluation method. Further, an atomic force microscope image (shape image and phase image) is shown in FIG.

Composition 3 for forming a low refractive index layer
Pentaerythritol triacrylate (PETA): 0.12 parts by mass Fluorine-containing compound ^{* 1} : 2.07 parts by mass Hollow silica particle dispersion ^{* 2} : 6.28 parts by mass Solid silica particle dispersion ^{* 3} : 0.7 mass Part Fluoropolymer ^{* 4} : 2.62 parts by mass Fluoromonomer ^{* 5} : 2.09 parts by mass Photopolymerization initiator ^{* 6} : 0.07 parts by mass Methyl isobutyl ketone: 56.96 parts by mass Propylene glycol monomethyl ether acetate: 29.1 parts by mass

Preparation Example 3: Preparation Example of Composition for Forming High Refractive Index Layer Rutile-type titanium oxide (“TTO51 (C) (trade name)”, manufactured by Ishihara Sangyo Co., Ltd., primary particle size: 0.01 to 0.03 μm): 10 parts by mass, anionic group-containing dispersant ("Disperbic 163 (trade name)", manufactured by Big Chemie Japan): 2 parts by mass, and methyl isobutyl ketone: 48 parts by mass in a mayonnaise bottle Produced. The resulting mixture was stirred for 10 hours with a paint shaker using about 4 times the amount of zirconia beads (φ0.3 mm) to prepare a composition for forming a high refractive index layer.

Preparation Example 4: Preparation Example of Medium Refractive Index Layer Composition In the above preparation example of the composition for forming a high refractive index layer, rutile titanium oxide was converted to antimony-doped tin oxide (“SN-100P (trade name)”, Ishihara Sangyo Co., Ltd.) and the preparation of the composition for forming a high refractive index layer except that the anionic group-containing dispersant is “Dispervic 111 (trade name)” (manufactured by Big Chemie Japan). Thus, a composition for forming a middle refractive index layer was prepared.

Example 4
The hard coat layer forming composition 1 is bar coated on a triacetyl cellulose (TAC) resin film having a thickness of 80 μm, dried at 50 ° C. for 1 minute, and after removing the solvent, an ultraviolet irradiation device ( Using a fusion UV system Japan Co., Ltd. light source H bulb), an ultraviolet ray was irradiated at an irradiation dose of 30 mJ / cm ² and cured to obtain a hard coat layer having a thickness of about 10 μm.
On the obtained hard coat layer, the composition for forming a medium refractive index layer obtained in Preparation Example 4 is bar-coated, cured by irradiation with ultraviolet rays at an irradiation dose of 200 mJ / cm ² , and a high thickness of about 120 nm. A refractive index layer is formed, and the composition for forming a high refractive index layer obtained in Preparation Example 3 is bar-coated, cured by irradiation with ultraviolet rays at an irradiation dose of 200 mJ / cm ² , and a high refractive index of about 60 nm in thickness. A layer was formed. Next, the following low refractive index layer-forming composition 4 is bar coated to form a coating film (step (1)), and subjected to a heat treatment at 50 ° C. for 1 minute so that the coating film is antifouling with a low refractive index phase. After phase separation into phases and removal of the solvent (step (2)), UV irradiation is performed at an irradiation dose of 200 mJ / cm ² to cure to form a low refractive index layer and an antifouling layer (step (step (2)). 3)), an antireflection film having a transparent substrate, a hard coat layer, a medium refractive index layer, a high refractive index layer, a low refractive index layer, and an antifouling layer was obtained. During the curing, the solvent was almost completely evaporated, and the total thickness of the low refractive index layer and the antifouling layer was about 100 nm. Further, when the atomic ratio was measured by X-ray photoelectron spectroscopy (XPS), atoms contained in the fine particles in the low refractive index layer were also detected. Considering that the thickness of the X-ray photoelectron spectroscopy (XPS) antifouling layer is 1 to 3 nm, the thickness of the obtained antifouling layer is estimated to be in the range of 1 to 3 nm.
Table 1 shows the results of evaluation of the obtained antireflection film by the above evaluation method. Further, an atomic force microscope image (shape image and phase image) is shown in FIG.

Composition 4 for forming a low refractive index layer
Pentaerythritol triacrylate (PETA): 0.32 parts by mass Fluorine-containing compound ^{* 1} : 0.71 parts by mass Hollow silica particle dispersion ^{* 2} : 6.42 parts by mass Solid silica particle dispersion ^{* 3} : 1.43 parts by mass Part Fluoropolymer ^{* 4} : 3.21 parts by mass Fluoromonomer ^{* 5} : 0.54 parts by mass Photopolymerization initiator ^{* 6} : 0.07 parts by mass Methyl isobutyl ketone: 58.2 parts by mass Propylene glycol monomethyl ether acetate: 29.1 parts by mass

Example 5
In Example 1, an antireflection film was obtained in the same manner as in Example 1 except that the composition 1 for forming a low refractive index layer was replaced with the composition 5 for forming a low refractive index layer described below. Table 1 shows the results of evaluation of the obtained antireflection film by the above evaluation method. Further, an atomic force microscope image (shape image and phase image) is shown in FIG.

Composition 5 for forming a low refractive index layer
Pentaerythritol triacrylate (PETA): 0.10 parts by mass Fluorine compound ^{* 10} : 1.23 parts by mass Hollow silica particle dispersion ^{* 2} : 6.69 parts by mass Solid silica particle dispersion ^{* 3} : 0.74 parts by mass Part Fluoropolymer ^{* 4} : 2.79 parts by mass Fluorine monomer ^{* 5} : 2.23 parts by mass Photopolymerization initiator ^{* 6} : 0.08 parts by mass Methyl isobutyl ketone: 57.04 parts by mass Propylene glycol monomethyl ether acetate: 29.1 parts by mass * 10, “X-71-1205 (trade name)”: manufactured by Shin-Etsu Chemical Co., Ltd., 20% by mass solution (solvent: mixture of methyl isobutyl ketone and methyl ethyl ketone, photocurable reactive group: (meth) A fluorinated compound having an acryloyl group, a reactive silane unit, and a silane unit having a perfluoropolyether group)

Example 6
In Example 1, an antireflection film was obtained in the same manner as in Example 1 except that the composition 1 for forming a low refractive index layer was replaced with the composition 6 for forming a low refractive index layer described below. Table 1 shows the results of evaluation of the obtained antireflection film by the above evaluation method.

Low refractive index layer-forming composition 6
Dipentaerythritol hexaacrylate (DPHA): 1.32 parts by mass Fluorine-containing compound ^{* 1} : 1.32 parts by mass Hollow silica particle dispersion ^{* 2} : 6.61 parts by mass Photopolymerization initiator ^{* 6} : 0.07 parts by mass Methyl isobutyl ketone: 61.03 parts by mass Propylene glycol monomethyl ether acetate: 29.1 parts by mass

Example 7
In Example 1, an antireflection film was obtained in the same manner as in Example 1 except that the composition 1 for forming a low refractive index layer was replaced with the composition 7 for forming a low refractive index layer described below. Table 1 shows the results of evaluation of the obtained antireflection film by the above evaluation method.

Low refractive index layer-forming composition 7
Pentaerythritol triacrylate (PETA): 0.10 parts by mass Fluorine-containing compound ^{* 1} : 2.93 parts by mass Hollow silica particle dispersion ^{* 2} : 5.86 parts by mass Solid silica particle dispersion ^{* 3} : 0.65 mass Part Fluoropolymer ^{* 4} : 2.44 parts by mass Fluoromonomer ^{* 5} : 1.95 parts by mass Photopolymerization initiator ^{* 6} : 0.07 parts by mass Methyl isobutyl ketone: 56.89 parts by mass Propylene glycol monomethyl ether acetate: 29.1 parts by mass

Example 8
In Example 1, an antireflection film was obtained in the same manner as in Example 1 except that the composition 1 for forming a low refractive index layer was replaced with the composition 8 for forming a low refractive index layer described below. Table 1 shows the results of evaluation of the obtained antireflection film by the above evaluation method.

Low refractive index layer forming composition 8
Pentaerythritol triacrylate (PETA): 1.32 parts by mass Fluorine-containing compound ^{* 1} : 1.32 parts by mass Hollow silica particle dispersion ^{* 2} : 6.61 parts by mass Photopolymerization initiator ^{* 6} : 0.07 parts by mass Methyl Isobutyl ketone: 61.03 parts by mass Toluene: 29.1 parts by mass

Example 9
In Example 1, an antireflection film was obtained in the same manner as in Example 1 except that the composition 1 for forming a low refractive index layer was replaced with the composition 9 for forming a low refractive index layer described below. Table 1 shows the results of evaluation of the obtained antireflection film by the above evaluation method.

Low refractive index layer-forming composition 9
Pentaerythritol triacrylate (PETA): 0.11 parts by mass Fluorine-containing compound ^{* 11} : 0.25 parts by mass Hollow silica particle dispersion ^{* 2} : 6.69 parts by mass Solid silica particle dispersion ^{* 3} : 0.74 parts by mass Part Fluoropolymer ^{* 12} : 2.79 parts by mass Fluorine monomer ^{* 5} : 2.23 parts by mass Photopolymerization initiator ^{* 6} : 0.08 parts by mass Methyl isobutyl ketone: 58.01 parts by mass Propylene glycol monomethyl ether acetate: 29.1 parts by mass * 11, “5101X (trade name)”: Solvay Specialty Polymers Japan Co., Ltd., a bifunctional tetrafunctional methacrylate-modified perfluoropolyether compound, and a fluorine-containing compound having no silane unit. )
* 12, “OPSTAR TU2224 (trade name)”, manufactured by JSR, 20% by mass solution (solvent: methyl isobutyl ketone)

Comparative Example 1
In Example 1, an antireflection film was obtained in the same manner as in Example 1 except that the composition 1 for forming a low refractive index layer was replaced with the composition 10 for forming a low refractive index layer described below. The results obtained by evaluating the obtained antireflection film by the above evaluation method are shown in Table 2. Further, an atomic force microscope image (shape image and phase image) is shown in FIG.

Composition 10 for forming a low refractive index layer
Pentaerythritol triacrylate (PETA): 0.12 parts by mass Fluorine-containing compound ^{* 1} : 0.52 parts by mass Hollow silica particle dispersion ^{* 2} : 7.04 parts by mass Solid silica particle dispersion ^{* 3} : 0.78 parts by mass Part Fluoropolymer ^{* 4} : 2.93 parts by mass Fluoromonomer ^{* 5} : 2.35 parts by mass Photopolymerization initiator ^{* 6} : 0.08 parts by mass Methyl isobutyl ketone: 57.09 parts by mass Propylene glycol monomethyl ether acetate: 29.1 parts by mass

Comparative Example 2
In Example 1, an antireflection film was obtained in the same manner as in Example 1 except that the composition 1 for forming a low refractive index layer was replaced with the composition 11 for forming a low refractive index layer described below. The results obtained by evaluating the obtained antireflection film by the above evaluation method are shown in Table 2. Further, an atomic force microscope image (shape image and phase image) is shown in FIG.

Composition 11 for forming a low refractive index layer
Pentaerythritol triacrylate (PETA): 0.09 parts by mass Fluorine-containing compound ^{* 1} : 3.79 parts by mass Hollow silica particle dispersion ^{* 2} : 5.44 parts by mass Solid silica particle dispersion ^{* 3} : 0.6 mass Part Fluoropolymer ^{* 4} : 2.27 parts by mass Fluoromonomer ^{* 5} : 1.81 parts by mass Photopolymerization initiator ^{* 6} : 0.06 parts by mass Methyl isobutyl ketone: 56.82 parts by mass Propylene glycol monomethyl ether acetate: 29.1 parts by mass

Comparative Example 3
In Example 1, an antireflection film was obtained in the same manner as in Example 1 except that the composition 1 for forming a low refractive index layer was replaced with the composition 12 for forming a low refractive index layer described below. The results obtained by evaluating the obtained antireflection film by the above evaluation method are shown in Table 2. Further, an atomic force microscope image (shape image and phase image) is shown in FIG.

Low refractive index layer forming composition 12
Pentaerythritol triacrylate (PETA): 0.32 parts by mass Hollow silica particle dispersion ^{* 2} : 6.42 parts by mass Solid silica particle dispersion ^{* 3} : 1.43 parts by mass Fluoropolymer ^{* 4} : 3.21 parts by mass Part Fluorinated monomer ^{* 5} : 0.54 part by weight Photopolymerization initiator ^{* 6} : 0.07 part by weight Methyl isobutyl ketone: 58.2 parts by weight Propylene glycol monomethyl ether acetate: 29.1 parts by weight

Comparative Example 4
In Example 1, an antireflection film was obtained in the same manner as in Example 1 except that the composition 1 for forming a low refractive index layer was replaced with the composition 13 for forming a low refractive index layer described below. The results obtained by evaluating the obtained antireflection film by the above evaluation method are shown in Table 2.

Low refractive index layer forming composition 13
Pentaerythritol triacrylate (PETA): 2.64 parts by mass Fluorine-containing compound ^{* 1} : 1.32 parts by mass Photopolymerization initiator ^{* 6} : 0.07 parts by mass Methyl isobutyl ketone: 95.42 parts by mass

Comparative Example 5
A solution having a solid content concentration of 3% by mass obtained by diluting the fluorine-containing compound used in Example 1 with metaxylene hexafluoride was prepared as an antifouling film deposition source.
A hard coat layer forming composition 1 is gravure-coated on a triacetyl cellulose (TAC) resin film having a width of 500 mm, a thickness of 80 μm, and a length of 500 m, and the following low refractive index layer forming composition 13 is prepared. After gravure coating, drying at 70 ° C. for 1 minute, removing the solvent, curing by irradiation with ultraviolet rays at an irradiation dose of 200 mJ / cm ² , and a hard coat layer with a thickness of about 10 μm and a low thickness of about 100 nm A refractive index layer was formed to obtain a laminate having a transparent substrate / hard coat layer / low refractive index layer.
Next, the antifouling film deposition source and the laminate are set in a wind-up type vapor deposition apparatus, and after evacuation to 1e ^-4 Torr or less, winding of the laminate starts at a traveling speed of 5 m / min. The antifouling film deposition source was evaporated with a non-contact heating type lamp heater to form an antifouling film on the low refractive index layer side of the laminate to obtain an antireflection film. The results obtained by evaluating the obtained antireflection film by the above evaluation method are shown in Table 2.

* 1, This is the amount (parts by mass) of the fluorine-containing compound with respect to 100 parts by mass (solid content) of the binder resin (including the fluorine-containing monomer and fluorine-containing polymer when these are used) and fine particles. Here, the solid content does not include a polymerization initiator.

The antireflection films obtained in Examples 1 to 5 are excellent in all evaluations, have excellent antireflection characteristics, have excellent scratch resistance and antifouling properties, and can be whitened. And a uniform and uniform surface from the results of contact angle and sliding angle. Further, Examples 1 to 5 have a uniform and uniform surface from the average surface roughness or the result of observation by an atomic force microscope, and the antifouling layer covers the entire surface on the low refractive index layer. It was confirmed that the film was uniformly and uniformly formed so as to cover it.
In Example 6 in which the binder resin was changed from PETA to DPHA, generally good physical properties were obtained. However, although the coated surface was generally uniform and uniform, the surface was slightly roughened and the scratch resistance was slightly decreased. Moreover, when DPHA was replaced with trimethylolpropane triacrylate (TMPTA) and pentaerythritol tetraacrylate (PETTA) to produce an antireflection film, it was confirmed that the same results as in Example 6 were obtained. In Example 7 where the content of the fluorine-containing compound was large, generally good physical properties were obtained, but the surface state was generally uniform and uniform, but slightly roughened, and the scratch resistance was slightly decreased. In Example 8 in which the glycol ether was replaced with toluene as the solvent, it was estimated that there was some influence on the dispersibility of the fine particles, and although the scratch resistance was slightly reduced, generally good results were obtained. From this result, it was confirmed that it is preferable to use ketones and glycol ethers as the solvent. Further, in Example 9 using the material used in Patent Document 2 as the fluorine-containing compound, the antifouling layer did not have a sea-island structure, and a good one without slight whitening was obtained. Was slightly inferior, and a slight distortion was confirmed. From this, it was confirmed that the fluorine-containing compound preferably has a silane unit.
In addition, in the antireflection films obtained in the examples, the total thickness of the low refractive index layer and the antifouling layer is about 100 nm, and the thickness of the antifouling layer is estimated to be in the range of 1 to 3 nm. The

On the other hand, in Comparative Example 1 in which the content of the fluorine-containing compound was small, the antireflection characteristics were the same as in the Examples, but since the silicon component was large, the antifouling property was not sufficient, and whitening was also confirmed. Moreover, it cannot be said that it has a uniform and uniform surface with a tumbling angle of 33 °, and the sea-island structure was confirmed from the observation result by an atomic force microscope. This sea-island structure is thought to have occurred because there was little fluorine-containing silane compound, so that the outermost surface of the low refractive index layer could not be covered and a uniform and uniform antifouling layer was not formed. It seems that it became a factor of whitening. In Comparative Example 2 containing an excessive amount of the fluorine-containing compound, excessive phase separation occurs in the entire low refractive index layer, the entire surface of the low refractive index layer is extremely rough, and a uniform and uniform antifouling layer is not formed. It was. This roughness is considered to be caused by the excessive fluorine-containing compound as a result of the protrusions of the fine particles in the low refractive index layer, resulting in the entire surface of the layer. Moreover, since the average surface roughness is large and the amount of the fluorine-containing compound contained in the antifouling layer is large, the antifouling layer becomes soft, and if it is wiped off during the evaluation of the antifouling property, there is a scratch. Oops. Further, in Comparative Example 3 that does not contain a fluorine-containing compound and the fluorine atom / carbon atom ratio is smaller than 0.6, a uniform surface was obtained, but the amount of fluorine was small, so that the antifouling property was not sufficient. There wasn't. Comparative Example 4 is an example in which fine particles were not used, but the entire coating film turned white when the coating film was dried due to poor compatibility between the binder resin and the fluorine-containing compound, and evaluation was possible. There wasn't. From this result, it is understood that the function of the fine particles is indispensable in order to maintain the balance between the binder resin and the fluorine-containing compound that is incompatible with the binder resin and to obtain a final target configuration. Further, in Comparative Example 5 in which the antifouling layer was formed by vapor deposition, the antifouling property and the surface state were generally good, but the reactive functional group in the antifouling phase and the low refractive index phase as in the present invention were used. Since there was no reaction curing with any reactive functional group, the adhesion between the antifouling layer and the low refractive index layer after curing was weak and the scratch resistance was poor.

According to the present invention, an antireflection film having excellent antireflection properties, excellent scratch resistance, and antifouling properties, and suppressing the occurrence of slight whitening that has never been questioned. Can be easily manufactured. The obtained antireflection film is suitably provided in a polarizing plate and an image display device.

Claims

It has at least a transparent substrate, a low refractive index layer, and an antifouling layer in order, including the following steps (1) to (3) in order, and measured by X-ray photoelectron spectroscopy (XPS) from the antifouling layer side The fluorine atom / carbon atom ratio is 0.6 to 1.0, the silicon atom / carbon atom ratio is less than 0.25, and the average surface roughness (Ra ′) of the antifouling layer is 10 nm or less. A method for producing an antireflection film.
Step (1) Step of forming a coating film by applying a composition for forming a low refractive index layer containing at least a fluorine-containing compound, fine particles and a binder resin on a transparent substrate (2) Low coating film with a low refractive index (3) Heating the low refractive index phase and the antifouling phase, or irradiating the low refractive index phase and the antifouling phase with ionizing radiation Forming a low refractive index layer and an antifouling layer covering the entire surface of the low refractive index layer
The method for producing an antireflection film according to claim 1, wherein the fluorine-containing compound has a reactive silane unit and a silane unit having a perfluoropolyether group.
The method for producing an antireflection film according to claim 2, wherein each of the reactive silane unit and the silane unit having a perfluoropolyether group has a siloxane skeleton.
The method for producing an antireflection film according to claim 2 or 3, wherein the reactive group is at least one selected from a (meth) acryloyl group and a vinyl group.
The method for producing an antireflection film according to any one of claims 1 to 4, wherein the fluorine-containing compound has a weight average molecular weight of 5,000 or more.
6. The method for producing an antireflection film according to claim 1, wherein the fine particles are silica fine particles.
The method for producing an antireflection film according to any one of claims 1 to 6, wherein the fine particles include fine particles having voids.
The method for producing an antireflection film according to any one of claims 1 to 7, wherein the fine particles are surface-treated.
The method for producing an antireflection film according to any one of claims 1 to 8, wherein the binder resin is an ionizing radiation curable resin.
The method for producing an antireflection film according to claim 9, wherein the ionizing radiation curable resin contains a tri- or higher functional (meth) acrylate.
An antireflection film produced by the method for producing an antireflection film according to any one of claims 1 to 10.
A polarizing plate having an antireflection film on at least one surface of the polarizing film, wherein the antireflection film is the antireflection film according to claim 11.
An image display device comprising an antireflection film or a polarizing plate having an antireflection film on at least one side of a polarizing film on the outermost surface of the display, wherein the antireflection film is the antireflection film according to claim 11.