JP2005148376A - Film and reflection preventing film - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a film in which film strength and adhesion to a base material are made superior, flexibility is provided and inorganic particulates having no rainbow unevenness on the surfaces and organic binder are included and to provide a reflection preventing film in which adhesion to the base material is made superior by providing a transparent film on the above film, flexibility is provided, no rainbow unevenness is provided and a superior reflection preventing function is provided. <P>SOLUTION: The film includes inorganic particulates and organic binder and the particulates are limitedly provided in the vicinity of one main surface of the film or have a density gradient in the film thickness direction. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a film and an antireflection film, and more specifically, a film containing inorganic fine particles and an organic binder, and an antireflection film having a transparent film on the film, thereby improving the film strength and the substrate. In addition to excellent adhesion, flexibility, flexibility, etc., various electrical and optical properties such as antistatic, electromagnetic shielding, magneto-optical effect, metallic luster, transparent conductivity, multilayer interference, etc. In particular, it is used for a display surface of an image display device such as a plasma display (PDP), a liquid crystal display (LCD), an electroluminescent display (EL), a cathode ray tube (CRT), a projection (PJTV), etc. And a suitable film, and an antireflection film having a transparent film on the film.

Conventionally, in order to impart various characteristics such as electrical characteristics and optical characteristics to a base material, generally, a film containing inorganic fine particles and an organic binder is formed on the base material. These films are required to be excellent in film strength, adhesion to substrates and other films, flexibility, flexibility, and the like.
However, in the conventional film containing inorganic fine particles and an organic binder, the inorganic fine particles used for imparting various characteristics such as electrical characteristics and optical characteristics are affected by the film strength, the substrate and other films. There has been a problem that adhesion, flexibility, flexibility, and the like are lowered.

  For example, in an image display unit of an image display device such as a conventional plasma display (PDP), liquid crystal display (LCD), electroluminescent display (EL), cathode ray tube (CRT), projection (PJTV), static electricity is easily charged. There are problems such as dust adhering to the static electricity, and external light or external shadow image reflected on the image display unit to obscure the image on the image display unit. In order to eliminate the problem, it is necessary to provide the image display unit of the image display device with functions such as antistatic, electromagnetic wave shielding, and antireflection.

  Therefore, a film having functions such as antistatic, electromagnetic wave shielding, and antireflection properties is formed on the surface of a transparent substrate constituting the image display unit. Examples of the film forming method include a method of forming a film by a vapor deposition method, a sputtering method, and the like, and a method of forming a film by a coating method. In either case, a method of forming a hard coat layer serving as a buffer layer between the transparent base material and the film is employed in order to maintain the film strength and prevent the occurrence of cracks and the like.

  As a structure having a hard coat layer, for example, a transparent hard coat layer is formed on a transparent plastic substrate, and a transparent conductive film and a transparent antireflection film are sequentially formed on the transparent hard coat layer by vapor deposition or sputtering. There is a filmed structure, or a structure in which a transparent hard coat layer is formed on a transparent plastic substrate, and a transparent conductive film and a transparent antireflection film are sequentially formed on the transparent hard coat layer by a coating method. This hard coat layer can be formed by applying a paint containing an inorganic filler such as metal oxide fine particles, an organic binder, an organic solvent, etc. on a substrate, and then drying and curing.

On the other hand, recent flat panel display devices (flat displays) are required to be further reduced in price as well as larger and thinner, and the manufacturing cost is reduced even when an anti-reflection function is added to the image display unit. Further reduction is required. Therefore, a structure in which an antireflection material in which an antireflection film is formed on the surface of a base material such as a transparent resin film is attached to the surface of the image display unit has been proposed.
Furthermore, in order to improve the adhesion between the surface of the transparent substrate and the various functional films, a structure in which a hard coat film is interposed between the transparent substrate and the various functional films has been proposed ( Patent Document 1).
JP 2001-21701 A

By the way, a film containing conventional inorganic fine particles and an organic binder, for example, a hard coat film, is required to have excellent film strength, adhesion to a substrate, and flexibility. A hard coat film satisfying all of the above characteristics has not been obtained.
For example, in the case of a paint containing a conventional inorganic filler such as metal oxide fine particles, an organic binder, an organic solvent, etc., it is necessary to add more metal oxide fine particles to further increase the film strength. However, when the amount of metal oxide fine particles added increases, the adhesion to the substrate decreases, especially when the substrate is a plastic film or plastic sheet, and the flexibility of the film also decreases. There was a problem of doing.

In addition, in the conventional hard coat film, color unevenness on the surface due to the film itself, that is, “surface rainbow unevenness” occurs, and particularly when used in an image display part of a display, it affects the visibility of a transmitted image. There was a problem such as giving. Furthermore, when an antistatic layer, an electromagnetic wave shielding layer, an antireflection layer, or the like is formed on the hard coat film, there is a problem that uneven color occurs in the image display portion due to reflected light.
For example, in the case of a transparent film with an antireflection film using a polyethylene terephthalate film (PETF) on a transparent plastic substrate, a strong “rainbow on the surface” occurs when the surface is observed under a three-wavelength fluorescent lamp. There was a problem that the quality of the appearance was lowered.
In addition, an antireflection film consisting of two layers, a transparent high refractive index layer and a transparent low refractive index layer, is used to exhibit antireflection performance. However, in a normal coating method, a transparent high refractive index layer, a transparent low refractive index layer, There were problems such as “reflection color unevenness” on the surface of the antireflection layer due to fine film thickness fluctuation of the refractive index layer, and deterioration in appearance quality.

  The present invention has been made in order to solve the above-mentioned problems, and is excellent in film strength and adhesion with a substrate, has flexibility, and has an inorganic fine particle having no rainbow unevenness on the surface and an organic system. By including a film containing a binder and a transparent film on this film, it has excellent adhesion to the substrate, has flexibility, has no rainbow unevenness on the surface, and has excellent antireflection performance An object is to provide an antireflection film.

  As a result of intensive studies, the present inventors have found that the inorganic fine particles are localized in the vicinity of one main surface of the film or the inorganic fine particles are in the thickness of the film. It has been found that by having a concentration gradient in the direction, a film having excellent film strength and adhesion to the substrate, flexibility, and no surface rainbow unevenness can be obtained, and the present invention has been completed. It was.

  That is, the film of the present invention is a film containing inorganic fine particles and an organic binder, and the inorganic fine particles are localized near one main surface of the film.

  Another film of the present invention is a film containing inorganic fine particles and an organic binder, wherein the inorganic fine particles have a concentration gradient in the thickness direction of the film.

In these films, the film is preferably a coating film,
The film is preferably a hard coat film.
The inorganic fine particles are preferably metal oxide fine particles.
The content of the inorganic fine particles in the film is preferably 5% by weight or more and 80% by weight or less.
The average primary particle diameter of the inorganic fine particles is preferably 2 nm or more and 80 nm or less, and the average dispersed particle diameter in the film is preferably 2 nm or more and 100 nm or less.

The difference in refractive index between both surfaces of the film is preferably 0.05 or more.
The film is formed on a substrate, and the difference in refractive index between the substrate-side surface of the film and the substrate is preferably within 0.1.
The refractive index of the inorganic fine particles is preferably 1.45 or more and 2.7 or less.
The difference between the critical surface tension of the inorganic fine particles and the critical surface tension of the organic binder is preferably 5 dyne / cm or more.
The film preferably contains a conductive polymer.

The antireflection film of the present invention comprises one or more transparent films on the film of the present invention.
In this antireflection film, the refractive index of the surface of the film on the transparent film side is preferably 1.50 or more and 1.72 or less.
It is preferable that at least one layer of the transparent film contains a light absorber having a maximum absorption wavelength of 400 nm to 500 nm, or 680 nm to 800 nm.

It is preferable that at least one layer of the transparent film contains spherical fine particles having an average dispersed particle diameter of 1.1 times or more and 1.6 times or less of the layer thickness.
The spherical fine particles preferably contain a light absorber having a maximum absorption wavelength of 400 nm to 500 nm, or 680 nm to 800 nm.
The surface density of the spherical fine particles is preferably 3 / μm ² or more and 30 / μm ² or less.
The transparent film has a plurality of layers, and the optical film thickness of the lowest refractive index layer in the plurality of layers is within a range of 140 nm ± 30 nm, and the optical film thickness of the highest refractive index layer is the lowest refractive index layer. The optical film thickness is preferably 1.2 times or more and 2.5 times or less.

It is preferable that at least one layer of the transparent film contains an organosiloxane or a fluorocarbon compound.
The organosiloxane or fluorocarbon compound is preferably modified with one or more selected from the group of alkyl groups, isocyanate groups, epoxy groups, acrylic groups, and alkyl silicon compounds.
The number of silicon atoms in the main chain of the organosiloxane is preferably 3 or more and 15 or less.
The fluorocarbon compound preferably has 3 or more and 10 or less carbon atoms.

According to the film of the present invention, the inorganic fine particles in the film containing the inorganic fine particles and the organic binder are localized near one main surface of the film. In the removed portion, the inorganic fine particles are not present, and as a result, only the organic binder is obtained. Therefore, the flexibility of the film itself can be increased.
Further, the required film strength can be obtained even when the content of the inorganic fine particles is small, and excellent adhesion and flexibility can be obtained even when the content of the inorganic fine particles is large. Unevenness can be eliminated.

According to another film of the present invention, the inorganic fine particles in the film containing the inorganic fine particles and the organic binder have a concentration gradient in the thickness direction of the film. By reducing the concentration of the inorganic fine particles on the side, the content of the organic binder can be relatively increased. Therefore, the flexibility of the film itself can be increased.
Further, the required film strength can be obtained even when the content of the inorganic fine particles is small, and excellent adhesion and flexibility can be obtained even when the content of the inorganic fine particles is large. Unevenness can be eliminated.

  According to the antireflection film of the present invention, since one or more transparent films are provided on the film of the present invention, the film has excellent adhesion and flexibility with the substrate, and also has an excellent antireflection effect. can do.

The best mode for carrying out the film and the antireflection film of the present invention will be described.
This embodiment is specifically described for better understanding of the gist of the invention, and does not limit the present invention unless otherwise specified.

[film]
The film of the present invention is a film containing inorganic fine particles and an organic binder, and is a film composed of any one of the following (1) and (2).
(1) Inorganic fine particles localized near one main surface of the film.
(2) The inorganic fine particles have a concentration gradient in the thickness direction of the film.
These films are preferably either a coating film or a hard coat film.

Here, “the inorganic fine particles are localized in the vicinity of one main surface of the film” means that the inorganic fine particles do not exist in the entire film, but the upper or lower surface portion in the film (near the main surface). ) Means that the inorganic fine particles are present at a higher concentration than other portions. The surface portion means a portion within 15% of the film thickness from the surface.
Further, it is preferable that 50% or more of the inorganic fine particles exist within a range of 15% of the film thickness from the surface, and more preferably 70% or more of the inorganic fine particles exist within a range of 10% of the film thickness from the surface.

  Furthermore, it is preferable that all inorganic fine particles exist within a range of 15% of the film thickness from the surface, and it is further preferable that all inorganic fine particles exist within a range of 10% of the film thickness from the surface. In this case, it is sufficient that almost all of the inorganic fine particles exist within the above range, and even if a very small amount of inorganic fine particles exist outside the above range, the effect of the present invention is not hindered.

  Moreover, “the inorganic fine particles have a concentration gradient in the thickness direction of the film” means that the concentration of the inorganic fine particles in the film is continuously from one main surface of the film toward the other main surface, Or the state which is increasing or decreasing stepwise, or the state which is changing continuously from one main surface of the film to the other main surface or stepwise.

  The film is required to have excellent film strength, adhesion to the substrate, and flexibility. However, the film of the present invention contains inorganic fine particles and an organic binder. Since the state is localized in the vicinity of one principal surface of the film or has a concentration gradient in the thickness direction of the film, the film has excellent film strength, adhesion to the substrate, and flexibility.

That is, in the film of the present invention, the inorganic fine particles are localized in the vicinity of one main surface of the film, for example, the inorganic fine particles are localized in the vicinity of the surface on the opposite side of the substrate, whereby the substrate and the film are in contact. The portion is only an organic binder, and can be firmly adhered to the substrate.
When the inorganic fine particles have a concentration gradient in the thickness direction of the film, for example, by reducing the concentration of the inorganic fine particles from the surface opposite to the substrate toward the substrate side, The portion in contact with the film increases the proportion of the organic binder, and can be firmly adhered to the substrate.
This is particularly noticeable when the substrate is a plastic sheet or a plastic film.

  In these cases, the surface on the side opposite to the base material has a higher proportion of inorganic fine particles, so that the strength of the film and the hardness of the surface are increased. Moreover, since these films have the above-described structure, they are excellent in flexibility. Therefore, the film of the present invention has high film strength even when the content of inorganic fine particles is small, and becomes a film excellent in adhesion to the substrate and flexibility.

Furthermore, when the film of the present invention is used as a hard coat film, even if the content of inorganic fine particles is small, the hard coat is satisfied in order to satisfy the characteristics of excellent film strength, adhesion to a substrate, and flexibility. It becomes a very excellent film.
Further, even when transparency is required for the hard coat film, the content of the inorganic fine particles that affect the transparency can be reduced, so that the hard coat film is excellent in transparency.

Examples of inorganic fine particles include metal fine particles such as gold, silver, platinum, copper, nickel, aluminum, tin, antimony, manganese and zinc, non-metallic fine particles such as carbon, silicon, molybdenum and tungsten, or these elements. Examples include oxides, nitrides, carbides, halides, etc. Among them, metal oxide fine particles are preferable.
As these inorganic fine particles, for example, from the viewpoint of increasing the film strength, for example, metal oxide fine particles such as aluminum oxide, antimony oxide, tin oxide, zirconium oxide, tantalum oxide, cerium oxide, titanium oxide, silicon oxide, molybdenum oxide, Non-metal oxide fine particles such as tungsten oxide can be used. Further, when a film containing these metal oxide fine particles or non-metal oxide fine particles is used as a hard coat layer, a hard coat layer excellent in transparency can be formed without being colored.

The content of the inorganic fine particles in the film is preferably 5% by weight or more and 80% by weight or less, more preferably 5% by weight or more and 60% by weight or less.
If the content of the inorganic fine particles is less than 5% by weight, sufficient film strength may not be obtained. If the content exceeds 80% by weight, the adhesion and flexibility with the substrate are reduced. This is because, in particular, when the film is a hard coat film, if transparency is required, the light transmittance may be reduced.

The average primary particle diameter of the inorganic fine particles is preferably 2 nm or more and 80 nm or less, and the average dispersed particle diameter in the film is preferably 2 nm or more and 100 nm or less.
This is because if the average dispersed particle size of the inorganic fine particles exceeds 100 nm, the film containing the inorganic fine particles appears to be white due to the significant scattering of light by Rayleigh scattering, and thus the transparency of the film is lowered.
The refractive index of the inorganic fine particles is preferably 1.45 or more and 2.7 or less.
This is because an antireflection effect is easily obtained when another transparent film is laminated on the film containing inorganic fine particles to form an antireflection film.

As the organic binder, for example, an ultraviolet curable resin, an electron beam curable resin, a cationic polymerization resin, a thermosetting resin, and the like can be appropriately selected and used.
Among them, the ultraviolet curable resin is preferably used because it is available at low cost and has excellent adhesion to a substrate, particularly a transparent plastic substrate.
The ultraviolet curable resin may be a photosensitive resin used in a coating method (wet coating method). For example, an acrylic resin, an acrylic urethane resin, a silicone resin, an epoxy resin, or the like is used to disperse inorganic fine particles. It is preferably used for reasons such as not impairing the properties.

The difference in refractive index between both surfaces of the film is preferably 0.05 or more.
The reason is that when another transparent film is laminated on the film to form an antireflection film, the film can also contribute to the antireflection effect.
By adopting any one of the constitutions (1) and (2), this film can obtain excellent film strength, adhesion to a substrate, flexibility, and transparency.

[Substrate with film]
A substrate with a film can be obtained by forming the film directly on the substrate or through another layer.
The substrate is not particularly limited, and a glass substrate, a plastic substrate, or the like is used, but a plastic substrate such as a plastic sheet or a plastic film is preferable. The plastic substrate is preferably a transparent plastic substrate such as a transparent plastic sheet or a transparent plastic film.

  The material of the plastic substrate is not particularly limited. For example, polyethylene terephthalate (PET), triacetyl cellulose, polycarbonate (PC), polyethersulfone (PES), polyacrylate, norbornene resin, It can be appropriately selected from amorphous polyolefin-based resins and the like. Further, the thickness of the plastic substrate is not particularly limited, and a film having a thickness of about 50 to 250 μm is usually used for a film and a sheet having a thickness of about 10 mm is used for a sheet.

In this film-coated substrate, the difference in refractive index between the substrate-side surface of the film and the substrate is preferably within 0.1.
This is because when the refractive index difference between the refractive index of the substrate and the film formed on the substrate is large in the reflection spectrum, a ripple (difference in the amplitude of the reflectance) is generated. This is because “rainbow on the surface” occurs.
This surface rainbow spot is noticeable when the surface is observed using a three-wavelength fluorescent lamp. Here, the three-wavelength fluorescent lamp has a slight difference in emission spectrum depending on the manufacturer, but obtains white light by mixing the wavelength spectra of the three primary colors red, green, and blue.

When the surface of the film is observed using this three-wavelength fluorescent lamp as a light source, rainbow unevenness on the surface is observed as a result of interference of reflected light of red, green, and blue.
In order to reduce or prevent the occurrence of rainbow unevenness on the surface, it is preferable to reduce the difference in ripple by setting the refractive indexes of the substrate and the film to the same value or approaching the same value. That is, the difference between the refractive index on the substrate side of the film formed on the substrate and the average refractive index on the surface of the substrate is preferably within 0.1.

However, when a transparent film is formed on a PET substrate with an easy adhesion layer, the refractive index of the transparent film formed on this PET substrate is adjusted to the refractive index calculated by the following formula (1). Or close.
N = Np- (Ns-Np) / 2 (1)
N: Refractive index of transparent film
Np: Refractive index of the easily adhesive layer
Ns: Average surface refractive index of PET substrate

In this film-coated substrate, the refractive index of the film can be adjusted by localizing the inorganic fine particles in the vicinity of one main surface of the film or by having a concentration gradient in the thickness direction of the inorganic fine particles. The refractive index of the film can be made close to the refractive index of the substrate. Furthermore, since the refractive index of this film changes from the base material side toward the side opposite to the base material, the difference in ripple is reduced, and the refractive index of the base material and the refraction of the film formed on the base material are reduced. “Rainbow unevenness” caused by the difference from the rate can be reduced and reduced.
For example, when a transparent plastic substrate is used as the substrate and the film of the present invention and the transparent high refractive index layer are sequentially formed on the substrate, the refractive index of the film is changed from the transparent plastic substrate side to the transparent high refractive index. It can be gradually increased to the layer side, and "rainbow on the surface" can be reduced and reduced.

In the substrate with a film, the difference between the critical surface tension of the inorganic fine particles and the critical surface tension of the organic binder is preferably 5 dyne / cm or more.
By making the critical surface tension of the inorganic fine particles constituting the film 5 dyne / cm or more smaller than the critical surface tension of the organic binder constituting the film, the inorganic fine particles are formed on the surface portion of the film. It becomes localized or has a concentration gradient in the thickness direction of the film.

  The critical surface tension of the inorganic fine particles can be adjusted by subjecting the surface of the inorganic fine particles to surface treatment (or surface modification) using a surface treatment agent (or surface modifier) such as a surfactant. Although it does not necessarily limit as a surface treating agent (or surface modifier), Nonionic surfactant whose HLB value is 4 or less or 10 or more, cationic surfactant which has a linear alkyl group, etc. are mentioned. It is done.

By performing such surface treatment (or surface modification), when a film is formed on a substrate by a coating method, the dispersion system changes when the solvent evaporates during drying after coating, and the surface treatment ( Alternatively, the familiarity between the inorganic fine particles subjected to surface modification) and the organic binder deteriorates, and the inorganic fine particles are extruded from the organic binder, so that the inorganic fine particles have a locality or a concentration gradient.
Here, the reason why the inorganic fine particles are not localized on the substrate side or the concentration on the substrate side is low is that the familiarity between the substrate and the organic binder is good, and the organic surface is first applied to the substrate surface. This is because a rich portion of the binder is formed.

The film of the present invention may contain a conductive polymer.
When the film contains a conductive polymer, the film also has conductivity and becomes a film having antistatic performance and electromagnetic wave shielding performance.
Although it does not restrict | limit especially as a conductive polymer, When the ease of handling etc. are considered, the photosensitive conductive resin used for the coating method (wet coating method), for example, an ultraviolet curable conductive resin, is preferable.

As this ultraviolet curable conductive resin, for example, an acrylic, acrylurethane, silicone, or epoxy resin containing a thiol group, a pyrrole group, or an ion conductive material is used for adhesion to a transparent plastic substrate. And is preferably used for the reason that the dispersibility of the inorganic fine particles contained in the film is not impaired.
By using this ultraviolet curable conductive resin, it is not necessary to heat at a high temperature when forming a film. Moreover, when using a transparent plastic base material for a base material, a film | membrane can be formed, without affecting a base material.
When a conductive polymer is contained in the film to form a conductive film, the surface resistance value of the conductive film is preferably 1 × 10 ¹¹ Ω / □ or less.
The film of the present invention thus obtained is suitable as a hard coat film.

Further, another transparent film may be formed on the film of the present invention.
For example, a multilayer antireflection film can be obtained by using the film of the present invention as a hard coat film and forming another transparent film having a refractive index adjusted on the hard coat film.
Moreover, you may form the transparent film for providing functions other than an antireflection function on the film | membrane of this invention. For example, an antireflection film having a two-layer structure having an excellent antireflection function can be obtained by sequentially forming a “high refractive index layer” and a “low refractive index layer” on the film of the present invention.

[Antireflection film]
An antireflection film can be obtained by forming one or more transparent films on the film of the present invention.
Here, a description will be given by taking as an example an antireflection film in which a hard coat film is formed on a substrate and a transparent high refractive index layer and a transparent low refractive index layer are sequentially formed on the hard coat film as a transparent film.

"Hard coat film"
In the hard coat film, the inorganic fine particles are localized in the vicinity of one main surface of the hard coat film, or the inorganic fine particles have a concentration gradient in the thickness direction of the hard coat film. It is possible to provide a difference in refractive index between both surfaces.

The difference in refractive index between both surfaces is preferably 0.05 or more. This is because the hard coat film has a refractive index difference of 0.05 or more between the both surfaces, so that the hard coat film becomes a film corresponding to the middle refractive index layer in the antireflection effect.
Here, the medium refractive index layer is a layer having a refractive index between the refractive index of the high refractive index layer and the refractive index of the low refractive index layer. The refractive index of the middle refractive index layer depends on the optical characteristics of the high refractive index layer and the low refractive index layer of the antireflection film, but the refractive index of the middle refractive index layer is an intermediate value between these layers. It is desirable to take.

  For example, when a transparent high refractive index layer and a transparent low refractive index layer are sequentially formed on the hard coat film, the refractive index on the side opposite to the base material of the hard coat film (transparent high refractive index layer side) is 1.50 or more. And 1.72 or less is preferable. As a result, the antireflection film has a structure corresponding to a three-layer structure of a medium refractive index layer, a high refractive index layer, and a low refractive index layer, and a visible light reflection bottom can be widely obtained in the reflection spectrum.

  In this hard coat film, the difference between the refractive index of the substrate-side surface and the refractive index of the substrate is preferably within 0.1. The reason is that when the refractive index difference between the hard coat film and the substrate is greater than 0.1, the reflectance amplitude (hereinafter referred to as ripple) occurs when measuring the reflection spectrum. This is because surface rainbow unevenness due to ripples occurs.

  In this hard coat film, the refractive index in the film has a continuous gradient due to the above configuration, and the refractive index gradually increases from the substrate side to the transparent high refractive index layer side of the hard coat film. When the reflection spectrum is measured, the difference in ripple becomes small, and “surface rainbow unevenness” caused by the difference in refractive index between the base material and the hard coat film can be reduced and reduced.

"Transparent high refractive index layer"
As the transparent high refractive index layer, a layer made of silicon alkoxide and / or a hydrolysis product thereof, or a layer in which high refractive index oxide fine particles are fixed in a silica matrix derived therefrom is used.

Preferred examples of the silicon alkoxide include tetraalkoxysilane compounds such as tetraethoxysilane (Si (OC ₂ H ₅ ) ₄ ) and tetramethoxysilane (Si (OCH ₃ ) ₄ ), alkyltrialkoxysilane compounds, and the like. Used.
The high refractive index oxide fine particles include antimony-containing tin oxide (ATO), tin-containing indium oxide (ITO), aluminum-containing zinc oxide, antimony-containing indium oxide (AIO), cerium oxide, zinc oxide, zirconium oxide, and oxidation. Metal oxide fine particles such as titanium and tantalum oxide can form a transparent high refractive index layer excellent in transparency and are preferably used.

  The average primary particle diameter of the high refractive index oxide fine particles is preferably 1 nm or more and 100 nm or less. The reason is that when the average primary particle size is less than 1 nm, when forming a film by a coating method, it tends to agglomerate at the time of coating, making it difficult to uniformly disperse the coating, and further increasing the viscosity of the coating. In addition, when the average primary particle diameter exceeds 100 nm, the resulting high refractive index layer remarkably diffuses light due to Rayleigh scattering, so that it appears white, and transparency is high. It is because it falls.

The content of the high refractive index oxide fine particles in the transparent high refractive index layer is preferably 50% by weight or more, more preferably 60 to 95% by weight. The reason for this is that when the content of the high refractive index oxide fine particles is less than 50% by weight, the content of silicon alkoxide and / or its hydrolysis product or silica derived therefrom is relatively increased. This is because a sufficient high refractive index layer cannot be obtained and the reflectance increases, and when the content of the high refractive index oxide fine particles exceeds 95% by weight, silicon alkoxide and / or its The high refractive index oxide fine particles cannot be fixed in the hydrolysis product or the silica matrix derived therefrom, and scratches are formed when the transparent low refractive index layer is formed on the transparent high refractive index layer. This is because it becomes easy to enter and causes appearance defects.
The refractive index of the transparent high refractive index layer is preferably 1.6 to 2.0.

Here, when a plastic substrate is used as the substrate, the transparent high refractive index layer contains a large amount of oxide fine particles, and the portion of the hard coat film in contact with the transparent high refractive index layer also contains a relatively large amount of oxide fine particles. . Further, the side of the hard coat film that contacts the base material contains no or very little oxide fine particles.
Thereby, the surface energy of each layer increases, and the wettability between each layer improves remarkably. Due to the effect of improving the wettability, the adhesion between the layers is increased, and a higher film hardness than before can be exhibited. Therefore, the adhesion between the hard coat film and the substrate and the adhesion between the hard coat film and the transparent high refractive index layer are improved.

[Transparent low refractive index layer]
As the transparent low refractive index layer, a layer made of silicon alkoxide and / or a hydrolysis product thereof, or a layer made of silica is used. The transparent low refractive index layer may contain low refractive index fine particles and the like as necessary.
As the low refractive index fine particles, fine particles such as fluorine-containing acrylic fine particles, polytetrafluoroethylene (polytetrafluoroethylene (PTFE) fine particles), and magnesium fluoride filler are preferably used.
The refractive index of the transparent low refractive index layer is preferably 1.35 to 1.50.

This anti-reflection film may further enhance the anti-reflection effect by forming other layers having different refractive indexes in addition to the above-described transparent high refractive index layer and transparent low refractive index layer. It may be formed.
In addition, the reflected light color can be achromatic for the purpose of reducing the reflected color (also referred to as the surface color). By making the color achromatic, it is possible to reduce the reflection colors such as blue and violet, which are characteristic of the antireflection film, and it is possible to form an antireflection film that approaches natural reflected light and is easy on the eyes.

In order to make the reflected light color achromatic, at least one of the transparent high refractive index layer, the transparent low refractive index layer, and other layers having different refractive indexes formed as necessary has a maximum absorption wavelength. A wavelength absorber (light absorber) having an (absorption wavelength peak) of 400 nm or more and 500 nm or less, or 660 nm or more and 800 nm or less may be contained alone or in combination.
By using these wavelength absorbers, it is possible to moderate the increase in the reflection spectrum on the low wavelength side and the long wavelength side, which is characteristic of the antireflection film, and reduce the reflection spectrum of the antireflection film in a wide wavelength range. In addition, the visibility reflectance is reduced.

In this transparent high refractive index layer, transparent low refractive index layer, or other layers having different refractive indexes, a wavelength absorber having a maximum absorption wavelength (absorption wavelength peak) of 400 nm or more and 500 nm or less, a maximum absorption wavelength (absorption wavelength peak) ) May contain either 660 nm or more and a wavelength absorber of 800 nm or less, or both of them may be contained. Further, a plurality of wavelength absorbers having a maximum absorption wavelength (absorption wavelength peak) of 400 nm or more and 500 nm or less may be used in combination, and a plurality of wavelength absorbers having a maximum absorption wavelength (absorption wavelength peak) of 660 nm or more and 800 nm or less. You may use it combining species.
These wavelength absorbers are preferably contained in the transparent high refractive index layer.

  Examples of the wavelength absorber include, but are not limited to, azo pigments such as monoazo lakes, monoazos, disazos, condensed azos, metal complex azos, phthalocyanines, acid dye lakes, basics Dye lake, anthraquinone, thioindigo, berylone, berylene, quinagridone, dioxazine, isoindolinone, quinophthalone, isoindoline, nitroso, alizarin lake, metal complex azomethine, alkali blue In addition, daylight fluorescent pigments and the like can be used alone or in combination.

  Specific examples of the wavelength absorber include, but are not limited to, monoazo pigment, quinacridone, iron oxide yellow, disazo pigment, phthalocyanine green, phthalocyanine blue, cyanine blue, flavanthrone yellow, diansuraquinolyl. Red, indanthrone blue, thioindigo bordeaux, perinone orange, perelenscar red, perylene red 178, perylene maroon, dioxazine violet, isoindolinone yellow, quinophthalone yellow, isoindoline yellow, nickel nitroso yellow, madder lake, copper Examples thereof include organic pigments such as azomethine yellow and aniline black.

Also, alkali blue, petal, chromium oxide, black iron, titanium yellow, cobalt blue, cerulean blue, cobalt green, viridian, cadmium yellow, cadmium red, vermilion, lithopone, yellow lead, molybdate orange, zinc chromate, ultramarine blue, manganese Mention may also be made of inorganic pigments such as violet, cobalt violet, emerald green, bitumen, carbon black, metal powder and the like.
Furthermore, dyes such as azo dyes, phthalicyanine dyes, carbonium dyes, quinoneimine dyes, methine dyes, quinoline dyes, nitro dyes, nitroso dyes, benzoquinone dyes, naphthoquinone dyes, naphthalimide dyes, and verinone dyes can also be mentioned.
These wavelength absorbers can be used alone or in combination.

In this antireflection film, the optical film thickness of the transparent high refractive index layer described above is such that the optical film thickness of the transparent low refractive index layer is in the range of 140 nm ± 30 nm, and the optical film thickness of the transparent low refractive index layer is It is preferably 1.2 times or more and 2.5 times or less, and more preferably 1.4 times or more and 1.9 times or less.
This “optical film thickness” is represented by the product of the actual film thickness of the thin film to be measured and the refractive index of the thin film, as shown in the following equation (2).
Optical film thickness = n × d (2)
Where n: refractive index of the film d: actual film thickness

  In the conventional film thickness design for antireflection, the optical film thickness of each of the transparent high refractive index layer and the transparent low refractive index layer is set to 1 / wavelength λ (hereinafter referred to as the bottom wavelength) at the target minimum reflectance. Generally, when the antireflection film is produced based on this film thickness design, the reflectance at the bottom wavelength is the lowest, but at the longer wavelength side and the lower wavelength side than that, As the reflectivity increases, the reflected color of the portion becomes stronger, and it exhibits a tight blue-purple to red-purple reflected color. Furthermore, it also increases the visibility reflectivity, which is an index of visual reflectivity. Connected.

  Moreover, the shape of the reflection spectrum is remarkably changed due to the minute film thickness fluctuation at the time of coating, and the color of the reflected light of the film is partially uneven in red or blue. For this reason, problems such as having to manage the film thickness at the time of coating within a very narrow range occur.

Therefore, as a result of various studies to suppress the increase in the reflectance on the long wavelength side and the low wavelength side, as described above, the optical film thickness of the transparent high refractive index layer is changed to the optical film of the transparent low refractive index layer. It was found that the problem can be solved by setting the thickness to be larger than the conventional thickness design, such as 1.2 times or more and 2.5 times or less of the thickness.
Using this method, by suppressing the increase in reflectivity in both the long-wavelength side and low-wavelength side regions, the film thickness at the time of coating against reflection color unevenness such as red and blue due to a slight film thickness deviation It is possible to give some degree of freedom to the management range.

  Furthermore, by combining a wavelength absorber having a maximum absorption wavelength (absorption wavelength peak) of 400 nm or more and 500 nm or less, or a wavelength absorber having a maximum absorption wavelength (absorption wavelength peak) of 660 nm or more and 800 nm or less, alone or in combination, Further, the reflected light color can be achromatic.

In this antireflection film, at least one layer of the transparent film, that is, a transparent high refractive index layer, a transparent low refractive index layer, or another layer having a different refractive index is 1.1 times or more of the layer thickness and 1.6. It is preferable to contain spherical fine particles having an average dispersed particle size of twice or less.
By adding spherical fine particles having an average dispersed particle diameter of 1.1 times or more and 1.6 times or less of the layer thickness to at least one of these layers, fine irregularities are imparted to the film surface; Become. Therefore, by generating weak diffuse reflection at the interface part, the intensity of the reflected color is lowered, and it becomes possible to blur the boundary part of the uneven color, which is observed later due to minute film thickness fluctuation at the time of coating. The reflection color unevenness can be reduced.

  Here, when the average dispersed particle size of the spherical fine particles is less than 1.1 times the layer thickness, the particles are taken into the film, and it is difficult to provide fine irregularities on the film surface, which is not preferable. If it exceeds 1.6 times, the light is remarkably diffusely reflected by Rayleigh scattering, so that it appears white and the transparency is lowered, which is not preferable.

The surface density of the spherical fine particles is preferably 3 / μm ² or more and 30 / μm ² or less.
If the surface density of the spherical fine particles is less than 3 particles / μm ² , the spherical fine particles are not sufficiently distributed on the surface, the unevenness becomes sparse, and it is difficult to obtain the effect of adding the spherical fine particles. When the surface density of the spherical fine particles exceeds 30 particles / μm ² , the spherical fine particles become excessive and light scattering increases, so that the film surface appears white and the transparency is lowered. .

As the spherical fine particles, transparent and uniform monodispersed spherical fine particles are preferably used. As the monodispersed spherical fine particles, monodispersed spherical fine particles mainly composed of a synthetic resin, for example, silicone beads, acrylic Beads and the like are preferred.
A light absorber having a maximum absorption wavelength of 400 nm or more and 500 nm or less, or 660 nm or more and 800 nm or less may be added to the spherical fine particles singly or in combination. By adding the above light absorber to the spherical fine particles, it becomes possible to further achromatic the reflected light color.

In this antireflection film, at least one layer of the transparent film, that is, any one of the transparent high-refractive index layer, the transparent low-refractive index layer, and another layer having a different refractive index contains an organosiloxane or a fluorocarbon compound. In particular, it is preferable that the outermost layer contains an organosiloxane or a fluorocarbon compound.
When organosiloxane or a fluorocarbon compound is contained in at least one layer of the transparent film, particularly the outermost layer, the contact angle with water exceeds 90 °, so that the antireflection film can be imparted with water repellency.

Since this water-repellent effect can be sustained for a long time, there is no risk that the effect will be reduced if it is rubbed with a cotton cloth or the like, and therefore, higher antifouling properties than before can be obtained. In particular, when the organosiloxane or fluorocarbon compound is incorporated in a silica matrix, it does not ooze out easily, and the antifouling property lasts for a long time, which is preferable.
As described above, from the viewpoint of the antireflection effect and the water repellent effect, it is preferable that the transparent low refractive index layer is the outermost layer and the transparent low refractive index layer contains an organosiloxane or a fluorocarbon compound.

Examples of the organosiloxane include dialkylalkoxysilane compounds. Among them, organopolysiloxane is preferably used, and dimethylpolysiloxane (silicone oil) is particularly preferably used.
The number of silicon atoms in the main chain of the organosiloxane is preferably 3 or more and 15 or less.
When the number of silicon is less than 3, sufficient water repellency cannot be obtained even if added because the molecular weight of the organosiloxane is small, and when the number of silicon exceeds 15, the molecular weight becomes too large and the molecular weight is too high. This is because the polarity is small, so that oil droplets are easily formed during coating adjustment or coating. In addition, there is a possibility of inhibiting the polymerization reaction of the silica binder.

Examples of the fluorocarbon compound include a fluoroalkylalkoxysilane compound, and among these, a fluorine oil in which a part of hydrogen of dimethylpolysiloxane (silicone oil) is substituted with fluorine is preferably used.
The fluorocarbon compound preferably has 3 or more and 10 or less carbon atoms.
When the number of carbon atoms is less than 3, sufficient water repellency cannot be obtained even when added because the molecular weight of the fluorocarbon compound is small, and when the number of carbon atoms exceeds 10, the molecular weight becomes too large. This is because the molecular polarity is small, and it tends to form oil droplets when the paint is adjusted or applied. In addition, there is a possibility of inhibiting the polymerization reaction of the silica binder.

The content of organosiloxane or fluorocarbon compound is preferably 0.01% by weight or more and 5.0% by weight or less based on the total weight of the thin film.
For example, when an organosiloxane or fluorocarbon compound is contained in the outermost transparent low refractive index layer in an amount of 0.01% by weight to 5.0% by weight, the contact angle of the film with respect to water is 90 ° or more, It exhibits water repellency and becomes slippery, improves the film strength of the antireflection film, particularly steel wool, and imparts antifouling properties.

  The reason why the content of the organosiloxane or fluorocarbon compound is limited as described above is that when the content is less than 0.01% by weight, the surface of the transparent low refractive index layer where the organosiloxane or fluorocarbon compound is the outermost layer is sufficient. Since the contact angle with respect to water is less than 90 ° and sufficient water repellency cannot be obtained, the effect of improving the film strength and antifouling property of the antireflection film cannot be obtained. It is. Further, if the content exceeds 5.0% by weight, the organosiloxane or fluorocarbon compound becomes excessive on the surface of the transparent low refractive index layer, so that the water contact angle exceeds 90 ° and sufficient water repellency is obtained. This is because, although obtained, the polymerization curing reaction and adhesion of silicon alkoxide and / or its hydrolysis product are inhibited, and the film strength of the antireflection film is lowered.

The organosiloxane is a modified organosiloxane modified with one or more selected from the group of alkyl groups, isocyanate groups, epoxy groups, acrylic groups, and alkyl silicon compounds in order to be immobilized on a silica matrix. Is preferred.
The alkyl silicon compound is an organic silicon compound having at least one alkyl group. In addition to silicon alkoxide, organoalkoxysilane in which a part of organosilane is substituted with an alkyl group is preferably used.
As the modified organosiloxane, modified organopolysiloxane, particularly modified dimethylpolysiloxane (modified silicone oil) obtained by modifying dimethylpolysiloxane (silicone oil) is preferably used.

The fluorocarbon compound is a modified fluorocarbon modified with one or more selected from the group of alkyl groups, isocyanate groups, epoxy groups, acrylic groups, and alkyl silicon compounds in order to be immobilized on a silica matrix. Carbon compounds are preferred.
As this modified fluorocarbon compound, a modified fluorine oil obtained by modifying a fluorine oil is preferably used.

Next, the manufacturing method of the hard coat film and antireflection film of this embodiment will be described.
Here, an explanation will be given by taking as an example an antireflection film in which a hard coat film is formed on a substrate and a transparent film comprising a transparent high refractive index layer and a transparent low refractive index layer is formed on the hard coat film.

[Hard coat film formation]
Inorganic fine particles and an organic binder are dissolved or dispersed in a solvent to prepare a coating material for forming a hard coat film. Various additives such as a dispersant may be added to the hard coat film-forming coating as necessary. By applying the obtained coating material for forming a hard coat film on the surface of the transparent substrate, drying the coating material at a predetermined temperature of room temperature (25 ° C.) or higher, and then irradiating the coating material with ultraviolet rays, A hard coat film is formed on the substrate.

The inorganic fine particles adjust the critical surface tension by subjecting the surface to surface treatment (or surface modification) with a surfactant or the like. Although it does not specifically limit as a surface treating agent (or surface modifier), HLB is 4 or less, or 10 or more nonionic surfactant, the cationic surfactant which has a linear alkyl group, etc. are suitable. Used for.
By performing this surface treatment (or surface modification), the difference between the critical surface tension of the surface of the inorganic fine particles and the critical surface tension of the organic binder constituting the hard coat film can be 5 dyne / cm or more. .

In the drying process, this hard coat film forming paint
(A) Inorganic fine particles are localized near one main surface of the film.
(B) The inorganic fine particles are unevenly distributed in the thickness direction of the film, and a concentration gradient is imparted to the inorganic fine particles in the film.
By selecting and proceeding either
(1) A film in which inorganic fine particles are localized in the vicinity of one main surface of the film.
(2) A film in which inorganic fine particles have a concentration gradient in the thickness direction of the film.
Any of the membranes can be obtained.

In this drying process, the solvent suddenly evaporates, the dispersion changes, and the familiarity between the inorganic fine particles that have undergone surface treatment (or surface modification) and the organic binder deteriorates. Since the inorganic fine particles (or the surface modification) are extruded from the organic binder, the inorganic fine particles are localized on the surface portion of the film, or the concentration gradient in the thickness direction so that the concentration on the substrate side becomes high. It will have.
Here, the reason why the inorganic fine particles are not localized on the surface portion on the substrate side or the concentration on the substrate side is not high is, for example, when a plastic substrate and an organic binder are used, the plastic substrate and the organic binder This is because a part rich in organic binder is formed on the surface of the base material before the inorganic fine particles move to the base material side.

The hard coat film-forming coating material is prepared by mixing inorganic fine particles, an organic binder, a dispersing agent, and the like in a solvent, and uniformly dispersing the mixture using an ultrasonic dispersing machine, a homogenizer, a sand mill, or the like. be able to.
The solvent is preferably an organic solvent, for example, alcohols such as methanol, ethanol, propanol, butanol, diacetone alcohol, ethylene glycol and hexylene glycol, esters such as methyl acetate and ethyl acetate, diethyl ether and ethylene. Preferable examples include ethers such as glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, diethylene glycol monomethyl ether and diethylene glycol monoethyl ether, and ketones such as acetone, methyl ethyl ketone and acetoacetate. These organic solvents may be used alone or in combination of two or more.

A hard coat film is formed by applying the hard coat film forming paint to one surface of a transparent substrate such as a glass substrate or a plastic substrate, and then irradiating the hard coat film forming paint with an ultraviolet ray or the like to crosslink. Is obtained.
The thickness of the hard coat film is preferably 0.5 μm or more and 20 μm or less, more preferably 0.5 μm or more and 2 μm or less.
This is because when the film thickness is 0.5 μm or less, sufficient film hardness cannot be expressed, and when it exceeds 20 μm, curling increases particularly when a transparent plastic substrate is used as the transparent substrate. .

The content of the inorganic fine particles is 3% by weight or more and 60% by weight or less, preferably within this range, the portion where the inorganic fine particles after coating and curing are localized, or the portion having a concentration gradient It is desirable to adjust the optical film thickness to a content that can be set to ¼ of the target bottom wavelength λ. As a result, not only the effect as a hard coat film is given, but also the same effect as when two layers of a hard coat layer and a medium refractive index layer are apparently obtained is obtained, and a higher performance antireflection film is obtained. be able to.
Various coating methods can be used as the coating method, and can be appropriately selected from, for example, a bar coating method, a gravure coating method, a slit coating method, a roll coating method, and a dip coating method.

[Formation of transparent film]
A transparent film having a two-layer structure comprising a transparent high refractive index layer and a transparent low refractive index layer is formed on the hard coat film.
(1) Formation of transparent high refractive index layer High refractive index oxide fine particles and silicon alkoxide and / or a hydrolysis product thereof are dissolved or dispersed in a solvent to obtain a transparent high refractive index layer forming coating material.
Various materials such as a dispersant, a wavelength absorber, and spherical fine particles may be added to the transparent high refractive index layer-forming coating as necessary.

This transparent high refractive index layer-forming coating material is prepared by adding high refractive index oxide fine particles, silicon alkoxide and / or a hydrolysis product thereof, and optionally added wavelength absorbers, spherical particles, dispersants, etc. It can be carried out by mixing with a solvent and uniformly dispersing by a commonly used dispersing means such as an ultrasonic disperser, a homogenizer, or a sand mill.
The silicon alkoxide is appropriately selected from tetraalkoxysilane compounds such as tetraethoxysilane (Si (OC ₂ H ₅ ) ₄ ) and tetramethoxysilane (Si (OCH ₃ ) ₄ ), alkyltrialkoxysilane compounds, and the like. Can be used. The solvent is preferably an organic solvent, and can be appropriately selected from the alcohols, esters, ethers, ketones and the like described above. These organic solvents may be used alone or as a mixture of two or more.

The obtained transparent high refractive index layer-forming coating material is applied on the hard coat film and dried to form a transparent high refractive index layer.
The coating method for the transparent high refractive index layer-forming coating material can be appropriately selected from, for example, a bar coating method, a gravure coating method, a slit coating method, a roll coating method, and a dip coating method.
The drying temperature is preferably within a range where the base material used does not undergo thermal deformation. Further, when using a transparent plastic substrate, for example, it can be dried in a temperature range of 70 ° C. or more and 130 ° C. or less. A desired film hardness can be obtained by adjusting the curing time.

(2) Formation of Transparent Low Refractive Index Layer Silicon alkoxide and / or its hydrolysis product is dissolved or dispersed in a solvent to obtain a transparent low refractive index layer forming coating.
Various additives such as a wavelength absorber, an organosiloxane, and a fluorocarbon compound may be added to the transparent low refractive index layer-forming coating as necessary.
As the silicon alkoxide, for example, a tetraalkoxysilane compound, an alkyltrialkoxysilane compound, a fluorine-containing alkyltrialkoxysilane compound, and the like can be appropriately selected and used.

The solvent is preferably an organic solvent, and can be appropriately selected from the alcohols, esters, ethers, ketones and the like described above. These organic solvents may be used alone or as a mixture of two or more.
The organosiloxane can be appropriately selected from dialkylalkoxysilane compounds, among which organopolysiloxane, particularly dimethylpolysiloxane (silicone oil) is preferred.
Moreover, as a fluorocarbon compound, it can select from a fluoroalkyl alkoxysilane compound suitably, and a fluorine oil is suitable especially.

The obtained transparent low refractive index layer-forming coating material is applied onto the transparent high refractive index layer, and dried at 70 to 130 ° C. for 1 minute or longer, for example, to form a transparent low refractive index layer.
The refractive index of the transparent low refractive index layer is preferably 0.1 or more smaller than the refractive index of the transparent high refractive index layer, and by forming such a transparent low refractive index layer, extremely excellent antireflection properties Will be shown.
At this time, by adjusting the film thickness after drying so that the optical film thickness becomes 140 nm, a transparent low refractive index layer having a bottom wavelength of around 600 nm can be formed. Note that the bottom wavelength is not limited to this value.

The coating method of the transparent low refractive index layer-forming coating material can be appropriately selected from, for example, a bar coating method, a gravure coating method, a slit coating method, a roll coating method, and a dip coating method.
The drying temperature is preferably within a range where the base material used does not undergo thermal deformation. Moreover, when using a transparent plastic base material, for example, it can be dried in the range of 70 to 130 ° C., but when cured at a low temperature of less than 70 ° C., the curing speed becomes slow, but the curing time is adjusted. By doing so, a desired film hardness can be obtained.

EXAMPLES Hereinafter, although this invention is demonstrated concretely by Examples 1-7 and Comparative Examples 1 and 2, this invention is not limited by these Examples.
[Example 1]
(1) Preparation of coating material A1 for forming transparent hard coat layer (transparent conductive film) 34.47 g of methyl ethyl ketone and 30 g of ethanol were mixed, and then nonionic surface treatment agent (Asahi Denka Co., Ltd .: Adecatol LA-875) 53 g was added and mixed. Further, 10.5 g of zirconium oxide fine particles (manufactured by Sumitomo Osaka Cement Co., Ltd .: average primary particle size is 30 nm) was added, and 10 using an ultrasonic homogenizer (manufactured by Central Science Co., Ltd .: Sonifier 450). Dispersion treatment was performed for a minute to obtain a uniform mixed solution. Thereafter, 24.50 g of a conductive polyfunctional acrylate compound (manufactured by Shin-Nakamura Chemical Co., Ltd .: NK Oligo U-201PA60) was mixed and stirred in this mixed solution to obtain a uniform transparent hard coat layer forming coating material A1.

(2) Preparation of Transparent High Refractive Index Layer Coating Material B1 Tetraethoxysilane 4.16g, 1N nitric acid 0.14g, pure water 1.8g and ethanol 4.05g were mixed in a solution. Add 1.8 g of titanium fine particles (manufactured by Nippon Aerosil Co., Ltd .: P25, average primary particle diameter is 21 nm), 10 g of propylene glycol monomethyl ether, and 78.05 g of ethanol, and disperse for 10 minutes using the ultrasonic homogenizer described above. A uniform transparent high refractive index layer-forming coating material B1 was obtained.

(3) Adjustment of transparent low refractive index layer-forming coating material C1 Tetramethoxysilane 7.6 g, 1 N nitric acid 0.23 g, pure water 9.0 g, methanol 73.02 g, propylene glycol monomethyl ether 10 g Then, 0.15 g of a modified silicone oil obtained by modifying silicone oil with alcohol (manufactured by Toray Dow Corning: SF8427) was mixed to obtain a uniform coating C1 for forming a transparent low refractive index layer.

(4) Preparation of substrate with antireflection layer After drying the coating A1 for forming a transparent hard coat layer on one surface of a PET film (Mitsubishi Chemical Polyester Film Co., Ltd .: T-600E) having a thickness of 100 μm by a bar coating method. The film was applied to a thickness of 1.5 μm, then dried in a dryer at 80 ° C. for 1 minute, and then irradiated with ultraviolet light using an ultraviolet irradiation device of a high-pressure mercury lamp peaking at a wavelength of 365 nm. (250 mJ) to form a transparent hard coat layer on the PET film.

Next, the transparent high refractive index layer-forming coating material B1 is applied on the transparent hard coat layer, and then dried at 100 ° C. for 1 minute in a dryer, and the transparent high refractive index layer is formed on the transparent hard coat layer. Laminated. Further, a coating C1 for forming a transparent low refractive index layer was applied on the transparent high refractive index layer, and then dried and cured at 100 ° C. for 10 minutes in a dryer. A material was prepared.
The optical film thickness of this transparent high refractive index layer was 200 nm, and the optical film thickness of the transparent low refractive index layer was 130 nm. Therefore, the optical film thickness of the transparent high refractive index layer was 1.54 times the optical film thickness of the transparent low refractive index layer.

[Example 2]
Preparation of transparent hard coat layer (transparent conductive film) coating A2 34.91 g of methyl ethyl ketone and 30 g of ethanol were mixed, and then 0.09 g of nonionic surface treatment agent (Asahi Denka Co., Ltd .: Adecatol LA-875) was added. Furthermore, 1.75 g of zirconium oxide fine particles (manufactured by Sumitomo Osaka Cement Co., Ltd .: average primary particle size is 30 nm) is added, and dispersed for 10 minutes using an ultrasonic homogenizer (manufactured by Central Science Co., Ltd .: Sonifier 450). Processing was performed to obtain a uniform mixed solution. Thereafter, 33.25 g of a conductive polyfunctional acrylate compound (manufactured by Shin-Nakamura Chemical Co., Ltd .: NK Oligo U-201PA60) was mixed and stirred in this mixed solution to obtain a uniform transparent hard coat layer forming coating material A2.
A substrate with an antireflection layer of Example 2 was produced according to Example 1 except that this transparent hard coat layer-forming coating material A2 was used.

[Example 3]
Preparation of transparent low refractive index layer-forming coating material C2 Tetramethoxysilane 6.08g, fluorine-containing alkyltrimethoxysilane (GE Toshiba Silicone Co., Ltd .: TSL8257) 0.66g, 1N nitric acid 0.23g, pure water 9.0 g, 73.88 g of methanol, 10 g of propylene glycol monomethyl ether, and 0.15 g of modified silicone oil obtained by modifying silicone oil with alcohol (SF8427 manufactured by Toray Dow Corning Co., Ltd.) are mixed to obtain a uniform transparent low refractive index. The paint for forming the rate layer was C2.
A substrate with an antireflection layer of Example 3 was produced according to Example 1 except that this transparent low refractive index layer-forming coating material C2 was used.

[Example 4]
Preparation of transparent low refractive index layer-forming coating material C3: 7.43 g of tetramethoxysilane, 0.23 g of 1N nitric acid, 9.0 g of pure water, 73.14 g of methanol, 10 g of propylene glycol monomethyl ether, and silicone oil And 0.15 g of modified silicone oil modified with alcohol (Toray Dow Corning: SF8427) are mixed and homogenized, and then fine silicon oxide particles (Aerosil TT600, manufactured by Nippon Aerosil Co., Ltd., average primary particle size is about 60 nm) (Secondary agglomeration type)) 0.05 g is added, and then a dispersion treatment is carried out with an ultrasonic homogenizer so that the dispersion average particle diameter is 160 to 190 nm. did.
A substrate with an antireflection layer of Example 4 was produced according to Example 1 except that this transparent low refractive index layer-forming coating material C3 was used.

[Example 5]
(1) Preparation of Transparent High Refractive Index Layer Coating Material B2 Tetraethoxysilane 4.16g, 1N nitric acid 0.14g, pure water 1.8g and ethanol 4.05g were mixed in a solution. Titanium fine particles (manufactured by Nippon Aerosil Co., Ltd .: P-25, average primary particle size is 21 nm), propylene glycol monomethyl ether 10 g, and blue pigment powder having an absorption peak at 670 to 720 nm (manufactured by Toyo Ink Co., Ltd .: CYANINE BLUE (BNRS) 0.15 g and ethanol 77.9 g were added and dispersed for 10 minutes using the above-described ultrasonic homogenizer to obtain a uniform transparent high refractive index layer-forming coating material B2.

(2) Preparation of transparent low refractive index layer-forming coating material C4 7.6 g of tetramethoxysilane, 0.23 g of 1N nitric acid, 9.0 g of pure water, and a yellow dye having an absorption peak at 480 nm (Bayer. AGleverkusen 0.24 g of ASTRAZON YELLOE), 72.78 g of methanol, 10 g of propylene glycol monomethyl ether, and 0.15 g of modified silicone oil obtained by modifying silicone oil with alcohol (SF8427, Toray Dow Corning) A uniform transparent low refractive index layer-forming coating material C4 was obtained.
A substrate with an antireflection layer of Example 5 was produced in the same manner as in Example 1 except that these transparent high refractive index layer forming coating B2 and transparent low refractive index layer forming coating C4 were used.

[Example 6]
Preparation of Transparent High Refractive Index Layer Coating Paint B3 4.16 g of tetraethoxysilane, 0.14 g of 1N nitric acid, 1.8 g of pure water, and 4.05 g of ethanol were mixed. Titanium oxide fine particles (Nippon Aerosil Co., Ltd .: P-25, average primary particle size is 21 nm) 1.8 g, propylene glycol monomethyl ether 10 g, wavelength absorbers having absorption peaks at 480 nm and 680 to 720 nm (manufactured by Midori Chemical Co., Ltd.) : MIR101) 0.24 g and 77.81 g of ethanol were added and dispersed for 10 minutes using the above-described ultrasonic homogenizer to obtain a uniform transparent high refractive index layer-forming coating material B3.
A substrate with an antireflection layer of Example 6 was produced in the same manner as in Example 1 except that this transparent high refractive index layer-forming coating material B3 was used.

[Example 7]
In order to set the bottom wavelength to 610 nm in accordance with a normal film thickness design method, the optical film thickness of each of the transparent high refractive index layer and the transparent low refractive index layer is set to 150 nm. A substrate with an antireflection layer was produced.

[Comparative Example 1]
Preparation of Transparent Hard Coat Layer (Transparent Conductive Film) Forming Coating Material A3 34.47 g of methyl ethyl ketone and 30 g of toluene were mixed, 0.53 g of sodium dodecyl sulfate was added and mixed as a dispersant, and further zirconium oxide fine particles (Sumitomo) 17.5 g of Osaka Cement Co., Ltd. (average primary particle size is 30 nm) was added, and dispersion treatment was performed for 10 minutes using the above-described ultrasonic homogenizer to obtain a uniform mixed solution.
Next, 17.5 g of a conductive polyfunctional acrylate compound (manufactured by Shin-Nakamura Chemical Co., Ltd .: NK Oligo U-201PA60) was mixed and stirred in this mixed solution to obtain a uniform transparent hard coat layer forming coating material A3.
A substrate with a transparent hard coat layer of Comparative Example 1 was prepared according to Example 1 except that this transparent hard coat layer forming coating A3 was used.

[Comparative Example 2]
Preparation of Transparent Hard Coat Layer (Transparent Conductive Film) Forming Coating Material A4 34.47 g of methyl ethyl ketone and 30 g of toluene were mixed, 0.89 g of sodium dodecyl sulfate was added and mixed as a dispersant, and further zirconium oxide fine particles (Sumitomo) 29.75 g (Osaka Cement Co., Ltd .: average primary particle size is 30 nm) was added, and dispersion treatment was performed for 10 minutes using the above-described ultrasonic homogenizer to obtain a uniform mixed solution.
Next, 5.25 g of a conductive polyfunctional acrylate compound (manufactured by Shin-Nakamura Chemical Co., Ltd .: NK Oligo U-201PA60) was mixed and stirred in this mixed solution to obtain a uniform transparent hard coat layer forming coating material A4.
A substrate with a transparent hard coat layer of Comparative Example 2 was produced according to Example 1 except that this transparent hard coat layer forming coating A4 was used.

[Evaluation]
About the base material with a transparent hard coat layer which formed the transparent hard coat layer on the PET film of Examples 1 and 2 and Comparative Examples 1 and 2, total light transmittance, haze value, surface resistance value, steel wool strength, adhesion The film appearance was evaluated for each item.
Moreover, about the base material with an antireflection layer which laminated | stacked the transparent hard-coat layer, the transparent high refractive index layer, and the transparent low refractive index layer one by one on the PET film of Examples 1-7, a total light transmittance, a haze value, minimum reflection Evaluation was made for each of the following items: rate, luminous reflectance, surface resistance, pencil hardness, steel wool strength, contact angle, adhesion, and film appearance.
Moreover, about each base material with an antireflection layer of Examples 1, 5, and 7, the reflection spectrum was measured.

Further, transmission electron microscope images (TEM images) of the transparent hard coat layers of Example 1 and Comparative Example 1 were observed.
The evaluation results of the above items are shown in Tables 1 and 2, the measurement results of the reflection spectra of Examples 1, 5, and 7 are shown in FIGS. 1 to 3, and the transmission electron microscope image of the transparent hard coat layer of Example 1 ( The TEM images are shown in FIG.

The above evaluation method is as follows.
Total light transmittance: according to Japanese Industrial Standard “JIS K 7105”
Measured with Izmeter Haze value: Same as above Minimum reflectance: Using ultraviolet / visible spectrophotometer V-570 (manufactured by JASCO Corporation)
Measures 5 ° specular reflectance Surface resistance value: Measured with Hiresta (Dia Instruments)

Pencil hardness: According to Japanese Industrial Standard “JIS K 5400”, under 1 kg load
Hardness steel wool strength of the pencil scratches does not stick: a load of 250g / cm ² to # 0000 steel wool
Measures the number of scratches generated after reciprocating 10 times with load Adhesiveness: 1 cm on the surface of the membrane according to Japanese Industrial Standard “JIS K 5400”
Cut each side of the corner at 1mm intervals, and stick the surface to the adhesive tape.
Measure the number of remaining meshes after three peeling tests with a contact angle: Kyowa Interface Chemical Co., Ltd .: measured with a dynamic contact angle measurement device Hard coat refractive index: Refractive index difference between both sides of the hard coat layer Ellipsometer
(Measured by JA Woollam Japan)

"Evaluation results"
In the substrates with transparent hard coat layers of Examples 1 and 2, compared with the substrates with transparent hard coat layers of Comparative Examples 1 and 2, even when the oxide fine particles to be added are remarkably small, conductivity, film strength, It was found that an antireflection transparent conductive film excellent in adhesion and flexibility was obtained.
Moreover, according to the cross-sectional TEM image of the film | membrane which apply | coated and hardened only the hard-coat layer of Example 1 shown in FIG. 4, oxide microparticles | fine-particles (a black granular part in a figure) are hard-coat layers (in the figure, white). It was confirmed that it was unevenly distributed only on the surface portion of (part), and hardly existed inside the hard coat layer. Thereby, it was found that the oxide fine particles were selectively localized on the upper portion of the hard coat layer.
On the other hand, in the hard coat layer of Comparative Example 1, oxide fine particles were dispersed throughout the hard coat layer.

Moreover, in the base material with an antireflection layer of Examples 1-7, the difference of the refractive index by the side of the base material side of a hard-coat layer and the refractive index by the side of a high refractive index layer is the direction of the refractive index by the side of a high refractive index layer. It turned out to be about 0.12.
For example, in the case of the film produced in Example 1, the layer thickness of the hard coat layer was about 1.5 μm, but the thickness of the high refractive index portion of the layer was about 0.1 μm. It was confirmed to be consistent with the results.

  Furthermore, when the critical surface tension of the organic binder used in Examples 1 to 7 and the zirconium oxide fine particles after the surface treatment was measured, the critical surface tension of the organic binder was 32 to 36 dyne / cm, whereas after the surface treatment. The critical surface tension of the zirconium oxide fine particles is 45 to 50 dyne / cm, and the difference between the critical surface tensions of both is sufficiently large. It was found that due to the difference in surface tension, forces to separate each other were generated, and a hard coat layer in which oxide fine particles as shown in FIG. 4 were selectively localized on the hard coat layer was formed.

Further, as shown in Examples 3 and 4, it was found that the visibility reflectance can be reduced by adding a fluorine-based material or fine particles to the transparent low refractive index layer.
In particular, in the case of adding fine particles, “reflection color unevenness” was hardly confirmed, and it was found that the reflection color unevenness due to addition of fine particles was effective.
In addition, as shown in Examples 1 and 7, the effect of alleviating the increase in reflectance on the longer wavelength side and the lower wavelength side than the bottom wavelength by adjusting the balance of the layer thicknesses of the high refractive index layer and the low refractive index layer. I found out that
Furthermore, as shown in Examples 5 and 6, it was found that the combined use of the addition of the wavelength absorber can further reduce the increase in reflectance on the longer wavelength side and the lower wavelength side than the bottom wavelength.

  The film and antireflection film of the present invention are excellent in film strength and adhesion to a base material, have flexibility, and have no rainbow unevenness on the surface, so that plasma displays (PD), liquid crystal displays ( It can be applied to various display devices such as LCD), electroluminescent display (EL), cathode ray tube (CRT), projection (PJTV), etc., as well as various window materials such as automobiles and buildings. The effect is also significant in the industrial field.

It is a figure which shows the measurement result of the reflection spectrum of Example 1 of this invention. It is a figure which shows the measurement result of the reflection spectrum of Example 5 of this invention. It is a figure which shows the measurement result of the reflection spectrum of Example 7 of this invention. It is a figure which shows the transmission electron microscope image of the transparent hard-coat layer of Example 1 of this invention.

Claims (23)

A film containing inorganic fine particles and an organic binder,
The inorganic fine particles are localized in the vicinity of one main surface of the film. A film containing inorganic fine particles and an organic binder,
The inorganic fine particles have a concentration gradient in the thickness direction of the film.   The film according to claim 1, wherein the film is a coating film.   The film according to claim 1, wherein the film is a hard coat film.   The film according to any one of claims 1 to 4, wherein the inorganic fine particles are metal oxide fine particles.   The film according to any one of claims 1 to 5, wherein the content of the inorganic fine particles in the film is not less than 5 wt% and not more than 80 wt%.   The average primary particle diameter of the inorganic fine particles is 2 nm or more and 80 nm or less, and the average dispersed particle diameter in the film is 2 nm or more and 100 nm or less. The membrane described.   The film according to any one of claims 1 to 7, wherein a difference in refractive index between both surfaces of the film is 0.05 or more.   9. The film according to claim 1, wherein the film is formed on a substrate, and a difference in refractive index between the substrate-side surface of the film and the substrate is within 0.1. 2. The membrane according to item 1.   The film according to any one of claims 1 to 9, wherein the refractive index of the inorganic fine particles is 1.45 or more and 2.7 or less.   The film according to any one of claims 1 to 10, wherein a difference between a critical surface tension of the inorganic fine particles and a critical surface tension of the organic binder is 5 dyne / cm or more.   The film according to claim 1, wherein the film contains a conductive polymer.   An antireflection film comprising one or more transparent films on the film according to any one of claims 1 to 12.   The antireflective film according to claim 13, wherein a refractive index of a surface of the film on the transparent film side is 1.50 or more and 1.72 or less.   The antireflection film according to claim 13 or 14, wherein at least one layer of the transparent film contains a light absorber having a maximum absorption wavelength of 400 nm to 500 nm, or 680 nm to 800 nm.   16. The spherical fine particles having an average dispersed particle diameter of 1.1 times or more and 1.6 times or less of the layer thickness are contained in at least one layer of the transparent film. Antireflection film.   The antireflection film according to claim 16, wherein the spherical fine particles contain a light absorber having a maximum absorption wavelength of 400 nm to 500 nm, or 680 nm to 800 nm. Areal density 3 / [mu] m ² or more and 30 / [mu] m ² claim 16 or 17 antireflection film, wherein the less is the spherical microparticles. The transparent film is composed of a plurality of layers,
Among the plurality of layers, the optical film thickness of the layer having the lowest refractive index is in the range of 140 nm ± 30 nm, and the optical film thickness of the layer having the highest refractive index is 1 of the optical film thickness of the layer having the lowest refractive index. The antireflection film according to any one of claims 13 to 18, wherein the antireflection film is 2 times or more and 2.5 times or less.   20. The antireflection film according to any one of claims 13 to 19, wherein at least one layer of the transparent film contains an organosiloxane or a fluorocarbon compound.   21. The organosiloxane or fluorocarbon compound is modified with one or more selected from the group consisting of an alkyl group, an isocyanate group, an epoxy group, an acrylic group, and an alkyl silicon compound. Antireflection film.   The antireflection film according to claim 20 or 21, wherein the number of silicon in the main chain of the organosiloxane is 3 or more and 15 or less.   23. The antireflection film according to claim 20, 21 or 22, wherein the fluorocarbon compound has 3 or more and 10 or less carbon atoms.

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