WO2011115228A1 - Anti-glare film, manufacturing method for same, polarizing plate and image display device - Google Patents

Abstract

Provided is an anti-glare film that has excellent anti-glare properties, can sufficiently suppress discoloration, has high contrast, and can prevent surface glare. The anti-glare film is provided with a light-permeable base material and a diffusion layer that has an uneven pattern on the surface and is formed on at least one surface of the light-permeable base material. The anti-glare film is characterized in that a coating solution, which includes a radiation-curable binder that comprises, as necessary components, microparticles (A) and a (meth)acrylate monomer, is coated onto at least one surface of the light-permeable base material, is dried to form a coating film, and then cured to form the diffusion layer, and in that 50% of the microparticles (A) within the diffusion layer form an agglomerated pair in which the line extending through the centers of both microparticles forms an angle of inclination relative to the surface of the above light-permeable surface.

Description

Antiglare film, method for producing antiglare film, polarizing plate and image display device

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

In an image display device such as a cathode ray tube display (CRT), a liquid crystal display (LCD), a plasma display (PDP), an electroluminescence display (ELD), and electronic paper, an optical layer for preventing reflection is usually provided on the outermost surface. The body is provided. Such an anti-reflection optical laminate suppresses the reflection of an image or reduces the reflectance by light diffusion or interference.

As one of the antireflection optical laminates, an antiglare film is known in which an antiglare layer having an uneven shape is formed on the surface of a transparent substrate. This anti-glare film can prevent deterioration of visibility by diffusing external light by the uneven shape of the surface. Moreover, since such an anti-glare film is usually installed on the outermost surface of the image display device, a certain degree of hard coat property is also required.

As a conventional anti-glare film, for example, a film in which an anti-glare layer is formed by coating a resin containing a filler such as silicon dioxide (silica) is known (for example, see Patent Documents 1 and 2).
As such a conventional anti-glare film, a type in which aggregated particles and inorganic and / or organic fillers are added to the resin to form an uneven shape on the layer surface, or a film having an uneven surface on the layer surface is laminated. There are types in which the concavo-convex shape is transferred, and types in which the concavo-convex shape is formed by phase separation using the compatibility of the compounds constituting the binder, such as two or more types of polymers.

Such a conventional anti-glare film is designed to obtain a light diffusing and anti-glare action by the action of the surface shape of the anti-glare layer in any type. It is necessary to increase the uneven shape on the surface. As a method for increasing the uneven shape of the surface of the antiglare layer, for example, a method of containing an aggregate formed by agglomerating fine particles in the antiglare layer is known. An antiglare layer containing particles in an aggregated form formed by aggregating certain primary particles is described.
However, the agglomerated particles in Patent Document 3 have an extremely small average primary particle size of 0.005 to 0.03 μm, and the agglomerated morphology obtained by aggregating a large number of such fine primary particles is arbitrarily controlled. This is practically difficult, and there is a problem that the uneven shape on the surface of the antiglare layer to be formed cannot be controlled to a desired shape.

For example, Patent Document 4 describes an optical laminate in which the total haze value and the internal haze value are in a specific relationship, and the antiglare layer having an uneven shape on the outermost surface includes aggregated fine particles.
However, in the antiglare layer described in Patent Document 4, no study has been made on the control of the aggregation state of the fine particles, and aggregates in which many fine particles are aggregated in the thickness direction of the antiglare layer, Aggregates aggregated in the in-plane direction were included. For this reason, in the optical laminated body described in Patent Document 4, a large number of large convex portions are formed on the surface of the antiglare layer, and generation of white browning cannot be sufficiently suppressed, and so-called surface glare is generated. In some cases, the visibility of the display screen may be reduced.

Further, for example, Patent Document 5 includes an antiglare layer containing an aggregate of fine particles, and the surface of the antiglare layer has a fine uneven shape with an arithmetic mean roughness Ra and a root mean square slope RΔq within a predetermined range. An antiglare film inside is described.
However, the antiglare layer described in Patent Document 5 is an aggregate of fine particles aggregated in the in-plane direction of the antiglare layer, and an antiglare layer containing such an aggregate provides sufficient antiglare performance. In addition to being unable to do so, aggregates aggregated in the in-plane direction increased reflected light, causing white-brownness.

Further, for example, Patent Document 6 describes an antiglare film in which the ten-point surface roughness of the surface of the antiglare layer is within a predetermined range, and describes that the antiglare layer contains particles of irregular aggregates. Has been.
However, in Patent Document 6, the aggregation state of the particles of the irregular aggregate contained in the antiglare layer is not examined, and the aggregate of particles aggregated in the height direction of the antiglare layer or the surface of the antiglare layer It is described that an aggregate in which particles are aggregated in an inward direction is contained in an antiglare layer. For this reason, in the anti-glare film described in Patent Document 6, a large number of large convex portions are formed on the surface of the anti-glare layer, and the generation of white brown cannot be sufficiently suppressed, and the so-called surface glare has a glittering shine. Or the visibility of the display screen may be reduced.

Japanese Patent Laid-Open No. 6-18706 Japanese Patent Laid-Open No. 10-20103 JP 2009-008782 A International Publication No. 2008-020587 JP 2008-233870 A JP 2008-191310 A

In view of the above situation, the present invention is excellent in anti-glare properties, can sufficiently suppress the occurrence of white brown, has high contrast, can suitably prevent occurrence of surface glare, etc., and also has a hard coat property. An object is to provide an antiglare film provided, a method for producing the antiglare film, a polarizing plate and an image display device to which the antiglare film is applied.

The present invention is an antiglare film comprising a light-transmitting substrate and a diffusion layer formed on at least one surface of the light-transmitting substrate and having a concavo-convex shape on the surface. A coating liquid containing fine particles (A) and a radiation curable binder containing a (meth) acrylate monomer as essential components is applied onto at least one surface of the light-transmitting substrate, dried, and coated The fine particles (A) in the diffusion layer are inclined with respect to the surface of the light-transmitting base material by 50% or more of the fine particles (A) in the diffusion layer. It is an anti-glare film characterized by forming two aggregates aggregated so as to form a corner.

In the antiglare film of the present invention, the inclination angle formed by the straight line connecting the centers of the two fine particles (A) forming the aggregate and the surface of the light-transmitting substrate is 20 to 70 °. It is preferable.
Moreover, it is preferable that the said coating liquid contains a layered inorganic compound further.
The layered inorganic compound is preferably talc.
Further, the content of the layered inorganic compound is preferably 2 to 40 parts by mass with respect to 100 parts by mass of the radiation curable binder.
The fine particles (A) are preferably styrene fine particles and / or acrylic-styrene copolymer fine particles.
Further, when the average particle size of the fine particles (A) was D _A, the D _A is the thickness T of the diffusion layer, it is preferable to satisfy the following formula (A).
(1.34 × D _A ) <T <(1.94 × D _A ) (A)
The coating liquid further contains organic fine particles (B), and the organic fine particles (B) in the diffusion layer preferably have a larger average particle diameter than the fine particles (A) in the diffusion layer.
The organic fine particles (B) in the diffusion layer are preferably not aggregated.
Moreover, it is preferable that the said coating liquid contains the solvent which swells organic fine particles (B).
The organic fine particles (B) in the diffusion layer have an impregnation layer impregnated with a radiation curable binder, and the average thickness of the impregnation layer is preferably 0.01 to 1.0 μm.
Further, when the average particle diameter of the organic fine particles (B) was D _B, said D _B is the thickness T of the diffusion layer, it is preferable to satisfy the following formula (B).
D _B <T (B)

The present invention also provides a method for producing an antiglare film comprising a light transmissive substrate and a diffusion layer formed on at least one surface of the light transmissive substrate and having a concavo-convex shape on the surface. A coating liquid containing a radiation curable binder containing fine particles (A) and (meth) acrylate monomers as essential components is applied on at least one surface of the light-transmitting substrate and dried to form a coating film And the step of curing the coating film to form the diffusion layer, and the fine particles (A) in the diffusion layer have a straight line connecting the centers of 50% or more of the surface of the light-transmitting substrate. It is also a method for producing an antiglare film, characterized in that aggregates are formed so as to form an inclination angle with respect to the film.

Moreover, this invention is a polarizing plate provided with a polarizing element, Comprising: The anti-glare film of this invention is provided on the surface of the said polarizing element, It is also a polarizing plate characterized by the above-mentioned.
The present invention is also an image display device comprising the antiglare film of the present invention or the polarizing plate of the present invention on the outermost surface.
Hereinafter, the present invention will be described in detail.

The antiglare film of the present invention has a light-transmitting substrate and a diffusion layer formed on at least one surface of the light-transmitting substrate and having an uneven shape on the surface.
The light transmissive substrate preferably has smoothness and heat resistance and is excellent in mechanical strength. Specific examples of the material forming the light-transmitting substrate include polyester (polyethylene terephthalate, polyethylene naphthalate), cellulose triacetate, cellulose diacetate, cellulose acetate butyrate, polyamide, polyimide, polyethersulfone, polysulfone, and polypropylene. , Thermoplastic resins such as polymethylpentene, polyvinyl chloride, polyvinyl acetal, polyether ketone, polymethyl methacrylate, polycarbonate, polyurethane, or cyclopolyolefin, preferably polyester (polyethylene terephthalate, polyethylene naphthalate), A cellulose triacetate is mentioned.

The light-transmitting substrate is preferably used as a flexible film-like body, but it is also possible to use these thermoplastic resin plates depending on the usage mode in which curability is required. Alternatively, a glass plate plate may be used.

The thickness of the light transmissive substrate is preferably 20 to 300 μm, more preferably an upper limit of 200 μm and a lower limit of 30 μm. When the light-transmitting substrate is a plate-like body, the thickness may exceed these thicknesses.
In addition, the above light-transmitting substrate has an anchor in addition to a physical treatment such as corona discharge treatment, plasma treatment, saponification treatment, oxidation treatment, etc., in order to improve adhesion when an antiglare layer is formed thereon. Application of a paint called an agent or a primer may be performed in advance.

In the antiglare film of the present invention, the diffusion layer comprises a coating liquid containing a radiation curable binder containing the fine particles (A) and a (meth) acrylate monomer as essential components, and at least the light transmissive substrate. It is formed by applying and drying on one surface to form a coating film and curing the coating film.
In the present specification, the monomer includes all molecules that can be a constitutional unit of the basic structure of the polymer film because the monomer film is cured by ionizing radiation. That is, if the oligomer or prepolymer is a basic unit of a cured film, the oligomer or prepolymer is also included.
In the present invention, the monomer preferably has a small weight average molecular weight of 5000 or less.
In the present invention, the diffusion layer is a cured coating layer unless otherwise specified.

The fine particles (A) are fine particles having an internal diffusion function in the diffusion layer and a function of forming convex portions on the surface of the diffusion layer.
FIG. 1 is a cross-sectional view schematically showing the state of aggregates in the diffusion layer.
As shown in FIG. 1, in the antiglare film 10 of the present invention, two fine particles (A) 13 aggregate in a diffusion layer 12 formed on at least one surface of a light-transmitting substrate 11. Aggregates are formed. The two fine particles (A) 13 forming the aggregate are aggregated so that a straight line connecting the centers thereof forms an inclination angle with respect to the surface of the light transmissive substrate 11.
Since the diffusion layer contains such an aggregate, the antiglare film of the present invention is excellent in antiglare property, can sufficiently suppress the occurrence of white brown, and also suitably prevents the occurrence of surface glare. It becomes possible.

In the anti-glare film of the present invention, the fine particles (A) in the diffusion layer are composed of two aggregates in which the straight lines connecting the centers of each other are aggregated so as to form an inclination angle with respect to the surface of the light-transmitting substrate. A collection is formed.
The above-mentioned "straight line connecting the centers of each other" refers to the cross section of the two fine particles (A) constituting the aggregate in the cross section obtained by cutting the diffusion layer of the antiglare film of the present invention in the thickness direction. This means a straight line connecting the centers of the shapes. The “center of the shape drawn by the cross section” means the center of the circle because the shape drawn by the cross section is usually a circle, and if the shape drawn by the cross section is other than a circle, it means the center of gravity of the cross section. .

The two fine particles (A) forming the aggregates preferably have an inclination angle of 20 to 70 ° formed by a straight line connecting the centers of the fine particles and the surface of the light-transmitting substrate. When it is less than 20 °, the antiglare property of the antiglare film of the present invention may be inferior, and the aggregates contained in the diffusion layer may reflect outside light to cause white brown. On the other hand, if it exceeds 70 °, the convex portion formed on the surface of the diffusion layer at the corresponding position of the agglomerate becomes too large, and the antiglare film of the present invention has problems such as occurrence of whitening and surface glare. May occur. A more preferable lower limit of the inclination angle is 30 °, and a more preferable upper limit is 60 °. When the tilt angle is within the above range, the balance of the antiglare performance, the anti-glare property, and the anti-glare property is extremely excellent.
In the present specification, when the tilt angle is less than 20 °, it is assumed that the two fine particles (A) are aggregated in parallel to the surface of the light-transmitting substrate, and the tilt angle is 70 °. In the case of exceeding the above, it is assumed that the two fine particles (A) are aggregated perpendicularly to the surface of the light-transmitting substrate.

In the antiglare film of the present invention, 50% or more of the fine particles (A) in the diffusion layer form the above-mentioned aggregate.
Here, “50% or more forms the above-mentioned aggregate” means that the cross-section of the diffusion layer is randomly divided into 20 fine particles (A by observation with a microscope such as SEM, transmission type, or reflection type optical microscope). ) Means that 10 or more fine particles (A) form the above-mentioned aggregates.
When the fine particles (A) forming the agglomerates are less than 50%, the anti-glare performance of the anti-glare film of the present invention is insufficient, and the occurrence of white-brown and surface glare can be sufficiently suppressed. It will disappear. The ratio of the fine particles (A) forming the aggregate is preferably 65%, more preferably 80%. When the lower limit of the proportion of the fine particles (A) forming the aggregate is 65%, the antiglare property and the ability to prevent white brown are more suitable, and when the lower limit of the proportion is 80%, sufficient Anti-glare and contrast can be obtained.
In the diffusion layer, the fine particles (A) not forming the above-mentioned aggregates are less than 50%. That is, the diffusion layer is an aggregate in which the number of single-particulate fine particles (A) and two fine particles (A) are aggregated perpendicularly or parallel to the surface of the light-transmitting substrate in the region described above. The total number of fine particles (A) constituting the aggregate and the number of fine particles (A) constituting the aggregate in which three or more fine particles (A) are aggregated randomly measured 20 fine particles (A). Sometimes it can be defined that it is less than ten.

Such fine particles (A) are preferably particles that are not swollen by the radiation curable binder and / or solvent in the coating liquid.
Here, “particles that are not swollen” include not only the case where the particles are not swollen by the radiation-curable binder and / or the solvent, but also a case where they are slightly swollen. In the case of “slightly swollen”, an impregnation layer similar to the organic fine particles (B) described later is formed on the fine particles (A) in the diffusion layer. Is smaller than the impregnated layer formed on the organic fine particles (B) and less than 0.1 μm.
Whether or not an impregnation layer is formed on the fine particles (A) in the diffusion layer can be determined by, for example, observing a cross section of the fine particles (A) in the diffusion layer with a microscope (SEM or the like). .
In the following description, the fine particles (A) in the diffusion layer are also referred to as “fine particles (A2)”.

Examples of the fine particles (A) that are not swollen by the radiation curable binder and / or solvent include inorganic fine particles such as silica fine particles, polystyrene resin, melamine resin, polyester resin, acrylic resin, olefin resin, or a combination of these. Examples include organic fine particles such as coalescence with a higher degree of crosslinking. These fine particles (A) may be used alone or in combination of two or more.
Of these, organic fine particles that can easily be controlled in refractive index and particle diameter are preferable, and since a difference in refractive index from the radiation curable binder is easily provided (the refractive index of a normal radiation curable binder is 1.48 to 1.54), melamine fine particles, polystyrene fine particles and / or acrylic-styrene copolymer fine particles are preferably used. In the following description, it is assumed that the fine particles (A) are organic fine particles. In the present specification, “resin” is a concept including resin components such as monomers and oligomers.
Here, when the organic fine particles made of an acrylic resin, a polystyrene resin and an acrylic-styrene copolymer are produced by a generally known production method, an acrylic-styrene copolymer resin may be used as a material. In the case of the core-shell type, there are polystyrene fine particles using fine particles made of acrylic resin for the core, and conversely acrylic fine particles using fine particles made of styrene resin for the core. Therefore, in this specification, the distinction between the acrylic fine particles, the polystyrene fine particles, and the acrylic-styrene copolymer fine particles is determined based on which resin has the closest characteristic (for example, refractive index) to the fine particles. . For example, if the refractive index of the fine particles is less than 1.50, acrylic fine particles are obtained, and if the refractive index of the fine particles is 1.50 or more and less than 1.59, acrylic-styrene copolymer fine particles are obtained, and the refractive index of the fine particles is 1. If it is 59 or more, it can be regarded as styrene fine particles.
Hereinafter, the fine particles may be referred to as “highly crosslinked” or “lowly crosslinked”, and the “highly crosslinked” and “lowly crosslinked” are defined as follows.
A mixture of toluene and methyl isobutyl ketone (mass ratio 8: 2) is mixed with a radiation curable binder (a mixture of pentaerythritol triacrylate (PETA), dipentaerythritol hexaacrylate (DPHA), and polymethyl methacrylate (PMMA) ( Mass ratio: PETA / DPHA / PMMA = 86/5/9)) A coating liquid containing 190 parts by mass with respect to 100 parts by mass is prepared.
Fine particles are immersed in the resulting coating liquid for 24 hours, and fine particles in which swelling is observed are defined as “low crosslinking”, and fine particles in which swelling is not observed are defined as “high crosslinking”.

Here, as described above, in order for the antiglare film to exhibit sufficient antiglare performance, it is preferable that a large convex portion is formed on the surface of the diffusion layer. For example, the diffusion layer has a large particle size. When fine particles are contained, large convex portions can be easily formed on the surface of the diffusion layer. However, when the diffusion layer contains fine particles having a large particle diameter, the surface is rough (the roughness of the image, such as the blurred outline of the display image to which the antiglare film of the present invention is applied). May occur and the image quality may deteriorate due to lack of precision. In addition, since it is necessary to thicken the diffusion layer in order to prevent fine particles from falling off, the formed anti-glare film may curl or cracks may occur due to curing shrinkage of the binder component when the diffusion layer is formed. There is a problem of doing.
As a result of diligent study, the inventors of the present invention selected relatively small fine particles as fine particles to be contained in the diffusion layer, while paying attention to the relationship between the antiglare performance of such a diffusion layer and the size of the fine particles to be contained. An anti-glare film capable of exhibiting sufficient anti-glare performance while avoiding the problems when the above-mentioned fine particles having a large particle diameter are selected by making the fine particles take a predetermined aggregation form in the diffusion layer. It was.
That is, in the present invention, as the fine particles (A) to be contained in the diffusion layer, those having a smaller particle size are selected as compared with the fine particles that have been conventionally added to exhibit sufficient antiglare performance. is there.

Specifically, the average particle diameter of the fine particles (A) is preferably in the range of 0.5 to 10.0 μm. When the thickness is less than 0.5 μm, the above-mentioned aggregate cannot be formed at a predetermined ratio, and the antiglare performance of the antiglare film of the present invention may be insufficient. On the other hand, when the thickness exceeds 10.0 μm, the uneven shape formed on the surface of the diffusion layer increases, and the anti-glare film of the present invention may cause whitening or surface glare. A more preferable lower limit is 1.0 μm, and a more preferable upper limit is 8.0 μm.
The average particle diameter of the fine particles (A) is the particle diameter in the coating film, and means the arithmetic average of the particles if each of the contained fine particles has a single shape. In the case of irregular-shaped fine particles having a fine particle size distribution, it means the particle size of the most existing fine particles by particle size distribution measurement. The particle diameter can be measured by a Coulter counter method or the like when only fine particles are present. However, since the fine particles present in the coating film may have a particle size different from the powder state due to swelling or the like, the average particle size of the fine particles (A) in the diffusion layer of the antiglare film of the present invention. Is preferably measured by transmission optical microscope observation or cross-sectional SEM photography.

In the antiglare film of the present invention, when the average particle diameter of the fine particles (A) forming the aggregates was D _A, from the positional relationship of the tilt angle of the two particles as described above (A), the aggregate When the inclination angle formed by the straight line connecting the centers of the two fine particles (A) to be formed and the surface of the light-transmitting substrate is defined as θ, the thickness of the aggregate in which the two fine particles (A) are adjacent to each other The height of the direction is
1 / 2D _A + D _A sin θ + 1 / 2D _A = D _A (1 + sin θ)
It becomes.
At this time, when approximate values of sin 20 ° ≈0.34 and sin 70 ° ≈0.94 are used, the height in the thickness direction of the aggregate when the tilt angle is 20 ° is (1.34 × D _A ), and the tilt angle is 70. Since the height of the aggregate in the thickness direction at (°) is (1.94 × D _A ), the above D _A satisfies the following formula (A) as the positional relationship with the thickness T of the diffusion layer. Is preferred.
(1.34 × D _A ) <T <(1.94 × D _A ) (A)
The average particle size D _A of the particulate (A) to form aggregates and the thickness T of the diffusion layer, it satisfies the relation of the formula (A), it can be suitably formed aggregates described above.
That is, when the diffusion layer thickness is 1.34 times or less of the average particle diameter, the slope formed by the straight line connecting the centers of the two fine particles (A) constituting the aggregate and the surface of the light-transmitting substrate is formed. The angle may be too small, and if it is 1.94 times or more, the inclination angle formed between the straight line connecting the centers of the two fine particles (A) constituting the aggregate and the surface of the light-transmitting substrate is formed. May become too large.
A more preferable range is the following formula (A ′) using approximate values of sin 30 ° ≈0.50 and sin 60 ° ≈0.87 from the positional relationship of the inclination angles of the two fine particles (A) described above.
(1.50 × D _A ) <T <(1.87 × D _A ) (A ′)
In addition, the thickness T of the diffusion layer means an average value of the thickness of the diffusion layer measured by the SEM photograph of the cross section of the antiglare film.
Further, unless otherwise noted, the D _A represents an average particle diameter of the fine particles (A) in the diffusion layer after curing.

In the antiglare film of the present invention, as the fine particles (A), for example, an antiglare film is prepared in advance with a coating solution using organic fine particles having different crosslinking degrees, and the organic fine particles conform to a preferable degree of impregnation. Can be selected and used.

The content of the fine particles (A) in the coating liquid is not particularly limited, but is preferably 0.5 to 30 parts by mass with respect to 100 parts by mass of the radiation curable binder described later. If it is less than 0.5 parts by mass, the antiglare performance of the antiglare film of the present invention may be insufficient, and surface glare may easily occur. On the other hand, when it exceeds 30 mass parts, the contrast of the image display layer using the anti-glare film of this invention may fall. The minimum with more preferable content of the said microparticles | fine-particles (A) is 1 mass part, and a more preferable upper limit is 20 mass parts. By being in this range, the above-mentioned effect can be further ensured.

The coating liquid preferably further contains organic fine particles (B).
The difference in refractive index between the organic fine particles (B) and the binder is preferably less than 0.04.
The organic fine particles (B) mainly form convex portions on the surface of the diffusion layer at positions corresponding to the organic fine particles (B), and are formed by containing such organic fine particles (B). Smooth unevenness can be formed in the diffusion layer to achieve both antiglare properties and contrast.

As the material constituting the organic fine particles (B), those which are swollen by a radiation curable binder and / or a solvent described later are preferable. Specifically, for example, a silicone resin, a polyester resin, a styrene resin, an acrylic resin, Examples include olefin resins, copolymers thereof, and the like. Among them, acrylic resins are preferably used, and further, the degree of cross-linking such as improving the cross-linking density when producing fine particles is changed. Resins are preferred. In the present specification, the “resin” is a concept including a resin component such as a reactive or non-reactive polymer, monomer or oligomer.
Here, when the organic fine particles made of an acrylic resin, a styrene resin, and an acrylic-styrene copolymer are produced by a generally known production method, an acrylic-styrene copolymer resin may be used as a material. Further, when the organic fine particles (B) are core-shell type fine particles, there are styrene fine particles using fine particles made of acrylic resin for the core, and conversely acrylic fine particles using fine particles made of styrene resin for the core. Therefore, in this specification, the distinction between the acrylic fine particles, the styrene fine particles, and the acrylic-styrene copolymer fine particles is determined based on which resin has the closest characteristic (for example, refractive index) to the fine particles. . For example, if the refractive index of the fine particles is less than 1.50, acrylic fine particles are obtained, and if the refractive index of the fine particles is 1.50 or more and less than 1.59, acrylic-styrene copolymer fine particles are obtained, and the refractive index of the fine particles is 1. If it is 59 or more, it can be regarded as styrene fine particles.

Examples of the cross-linked acrylic resin include acrylic monomers such as acrylic acid and acrylic acid ester, methacrylic acid and methacrylic acid ester, acrylamide and acrylonitrile, a polymerization initiator such as persulfuric acid, and a cross-linking agent such as ethylene glycol dimethacrylate. A homopolymer or a copolymer obtained by polymerization using a suspension polymerization method or the like is preferable.
As the acrylic monomer, a cross-linked acrylic resin obtained using methyl methacrylate is particularly suitable. In addition, the thickness of the impregnation layer described later can be controlled by adjusting the degree of swelling by the radiation curable binder and / or solvent described later. For this purpose, the impregnation amount of the radiation curable binder is within a preferable range. It is preferable to change the degree of crosslinking so that

The average particle size of the organic fine particles (B) is not particularly limited, but may be equal to the average particle size of the fine particles (A) described above. However, the organic fine particles (B) in the diffusion layer preferably have a larger average particle diameter than the fine particles (A2) in the diffusion layer. When the average particle size of the organic fine particles (B) in the diffusion layer is equal to or smaller than the average particle size of the fine particles (A2) in the diffusion layer, the effect of adding the fine particles (A) can hardly be obtained. Sometimes.

Further, when the average particle diameter of the diffusion layer of the organic fine particles (B) was D _B, said D _B is the thickness T of the diffusion layer, it is preferable to satisfy the following formula (B) .
D _B <T (B)
The average particle size D _B of the organic fine particles (B) is, if not satisfied the above formula (B), i.e., the average particle size D _B of the organic fine particles (B) is a thickness T greater than or equal to the diffusion layer In some cases, the uneven shape formed on the surface of the diffusion layer by the organic fine particles (B) becomes large, the hard coat property of the antiglare film of the present invention is inferior, and the contrast when applied to an image display device is lowered. It may cause.

In the antiglare film of the present invention, the organic fine particles (B) in the diffusion layer preferably have an impregnation layer impregnated with a radiation curable binder described later. In the following description, the organic fine particles (B) on which the impregnation layer is formed, that is, the organic fine particles (B) in the diffusion layer are also referred to as “organic fine particles (B2)”.
By having the impregnation layer, the organic fine particles (B2) have extremely excellent adhesion to the cured product of the radiation curable binder (hereinafter also referred to as binder resin) of the diffusion layer. In addition, the impregnation layer in the organic fine particles (B2) is formed in a state where the radiation curable binder and the material constituting the organic fine particles (B2) are mixed. The refractive index is between the refractive index of the curable binder and the refractive index of the organic fine particles (B), and the transmitted light of the diffusion layer is reflected at the interface between the organic fine particles (B2) (impregnated layer) and the binder resin. It can be suitably reduced. At the same time, the impregnated layer has an appropriate layer thickness, and the center of the organic fine particles (B2) maintains the refractive index of the initial organic fine particles (B), so that the internal diffusion does not decrease. Therefore, it becomes possible to suitably prevent surface glare.
Further, as will be described later, the impregnated layer is a layer formed by swelling the organic fine particles (B) with the radiation curable binder and / or solvent. Therefore, the organic fine particles (B2) are extremely Fine particles with high flexibility. For this reason, the shape of the convex part formed in the position corresponding to the organic fine particles (B2) on the surface of the diffusion layer can be made gentle. This point will be described in more detail later.

The impregnation layer is a layer formed by impregnating a radiation curable binder from the outer surface of the organic fine particles (B2) in the diffusion layer toward the center thereof. The impregnated layer is a layer formed by impregnating mainly low molecular weight components of the radiation curable binder, that is, monomers, and polymers and oligomers that are polymers of the radiation curable binder that is a high molecular weight component. Difficult to impregnate. However, even an oligomer or a polymer may have a relatively small molecular weight or may be impregnated together when the monomer is impregnated.
The impregnated layer can be identified, for example, by observing a cross section of the organic fine particles (B2) in the diffusion layer with a microscope (SEM or the like).
The radiation curable binder impregnated in the impregnation layer may be impregnated with all the constituent components, or may be impregnated with a part of the constituent components.

The impregnated layer preferably has an average thickness of 0.01 to 1.0 μm. If it is less than 0.01 μm, the effect obtained by forming the above-mentioned impregnation layer may not be sufficiently obtained. If it exceeds 1.0 μm, the internal diffusion function of the organic fine particles (B2) is sufficiently exhibited. The effect of preventing surface glare may not be obtained sufficiently. The more preferable lower limit of the average thickness of the impregnated layer is 0.1 μm, and the more preferable upper limit is 0.8 μm. By being in this range, the above-mentioned effect can be exhibited more. Further, the diameter of the portion where the impregnated layer of the organic fine particles (B2) is not formed is preferably equal to or greater than the wavelength of light from the viewpoint of securing the internal diffusion function and preventing surface glare.
The average thickness of the impregnated layer means the average value of the thickness of the impregnated layer of organic fine particles (B2) observed in the cross-sectional SEM photograph of the antiglare film. Specifically, the cross section of the diffusion layer is 3000 to 50,000 times by SEM, and after observing and photographing any 5 scenes in which at least one fine particle with an impregnation layer is present, The thickness can be obtained as a value obtained by measuring two points for each fine particle and averaging 10 measured values. The thickness of the impregnated layer is measured by selecting two points where the boundary between the binder resin and the fine particles around the fine particles is relatively clear and the maximum impregnation is performed.

Here, the organic fine particles generally have a cross-linked structure, but the degree of swelling by the radiation curable binder and / or solvent varies depending on the degree of the cross-linking, and the organic fine particles usually have a high degree of cross-linking. If so, the degree of swelling becomes low, and if the degree of crosslinking is low, the degree of swelling becomes high. For this reason, for example, when the material constituting the organic fine particles (B) is the above-mentioned crosslinked acrylic resin, the thickness of the impregnated layer of the organic fine particles (B2) appropriately adjusts the degree of crosslinking of the crosslinked acrylic resin. By doing so, it can be controlled within a desired range. Further, from the viewpoint of antireflection performance and surface glare prevention, it is more preferable that the organic fine particles (B2) have a higher degree of cross-linking toward the central portion, and the inner side than the thickness of the impregnated layer of the organic fine particles (B2) is impregnated. Most preferably, the degree of crosslinking is not low and the degree of crosslinking is as low as the surface. The same applies to the fine particles (A) described above.

When the average particle diameter of the organic fine particles (B) is D _B 1 and the average particle diameter of the organic fine particles (B2) in the diffusion layer is D _B 2, the D _B 1 and D _B 2 are as follows: It is preferable to satisfy the formula (2).
0.01 μm <D _B 2−D _B 1 <1.0 μm (2)
In the above formula (2), when “D _B 2 -D _B 1” is 0.01 μm or less, the thickness of the impregnated layer becomes too thin, and the effect obtained by forming the above impregnated layer is obtained. There are times when you can't. If “D _B 2 -D _B 1” is 1.0 μm or more, the unevenness formed on the surface becomes too large, and the internal diffusion function is not sufficiently exhibited, and the effect of preventing surface glare can be sufficiently obtained. There may not be.
The more preferable lower limit of the above “D _B 2-D _B 1” is 0.1 μm, and the more preferable upper limit is 0.5 μm. When “D _B 2 -D _B 1” is within this range, the above-described effects can be further exerted.

In the antiglare film of the present invention, when the organic fine particles (B) have an impregnated layer in the diffusion layer, the organic fine particles (B) may have, for example, organic fine particles having different degrees of crosslinking in advance. An anti-glare film may be prepared with a coating solution using, and organic fine particles matching a preferable degree of impregnation may be selected and used.

Further, when the impregnated layer is formed on the organic fine particles (B) in the diffusion layer, the antiglare film of the present invention has an average particle diameter of the fine particles (A) and the organic fine particles (B) described above as D. _{When A} 1 and D _B 1 and the average particle diameters of the fine particles (A2) and the organic fine particles (B2) in the diffusion layer are D _A 2 and D _B 2, respectively, D _A 1, D _B 1, D _A 2 and D _B 2 preferably satisfy the following formula (3).
1.0 μm> D _B 2-D _B 1> D _A 2-D _A 1 ≧ 0 (3)
By satisfying the above formula (3), the uneven shape on the surface of the diffusion layer is made smooth, and the change in the refractive index of the particles due to the impregnation of the binder or the like into the particles contributing to internal diffusion can be suppressed. The internal diffusion can be easily maintained, and the reflection on the surface of the particles in the diffusion layer can be reduced, so that the antiglare film of the present invention can be more reliably prevented from whitening and surface glare.

The organic fine particles (B) are preferably not aggregated in the thickness direction (longitudinal direction) of the diffusion layer in the diffusion layer. When the organic fine particles (B) in the diffusion layer are aggregated so as to be stacked in the thickness direction of the diffusion layer, a large convex portion is formed on the surface of the diffusion layer at a position corresponding to the aggregated organic fine particles (B). In the antiglare film of the present invention, white brown or surface glare may occur. In addition, aggregation of the organic fine particles (B) in the diffusion layer can be suitably prevented by containing, for example, a layered inorganic compound described later. In the case where the aggregation of the organic fine particles (B) is in the direction perpendicular to the thickness direction of the diffusion layer (lateral direction), the above problem is less likely to occur than the aggregation in the vertical direction. Since a similar problem also occurs, it is preferable to add a layered inorganic compound as in the case of aggregation in the vertical direction.

The content of the organic fine particles (B) in the coating solution is not particularly limited, but is preferably 0.5 to 30 parts by mass with respect to 100 parts by mass of the radiation curable binder described later. If the amount is less than 0.5 part by mass, a sufficient uneven shape cannot be formed on the surface of the diffusion layer, and the antiglare performance of the antiglare film of the present invention may be insufficient. On the other hand, when the amount exceeds 30 parts by mass, aggregation of the organic fine particles (B) is likely to occur in the coating liquid, aggregation in the vertical or horizontal direction described above occurs in the diffusion layer, and the surface of the diffusion layer is large. Protrusions may be formed and white browning or surface glare may occur. The minimum with more preferable content of the said organic fine particle (B) is 1.0 mass part, and a more preferable upper limit is 20 mass parts. By being in this range, the above-mentioned effect can be further ensured.

In the antiglare film of the present invention, the radiation curable binder contains a (meth) acrylate monomer as an essential component.
By including the (meth) acrylate monomer as an essential component, the diffusion layer can include the above-described aggregate without impairing hard coat properties.
As such a radiation curable binder, those that swell the organic fine particles (B) described above are preferably exemplified, and those having transparency are preferred, and examples thereof include ionizing radiation curable resins that are cured by ultraviolet rays or electron beams. It is done. In the present specification, “(meth) acrylate” refers to methacrylate and acrylate.

Examples of the (meth) acrylate monomer include compounds having one or more unsaturated bonds such as a compound having a (meth) acrylate functional group.
Examples of the compound having one unsaturated bond include ethyl (meth) acrylate, ethylhexyl (meth) acrylate, styrene, methylstyrene, N-vinylpyrrolidone and the like. Examples of the compound having two or more unsaturated bonds include polymethylolpropane tri (meth) acrylate, hexanediol di (meth) acrylate, polypropylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, pentaerythritol tri ( (Meth) acrylate, pentaerythritol penta (meth) acrylate, polyethylene glycol di (meth) acrylate, bisphenol F EO modified di (meth) acrylate, bisphenol A EO modified di (meth) acrylate, trimethylolpropane tri (meth) acrylate, di Pentaerythritol penta (meth) acrylate, isocyanuric acid EO-modified di (meth) acrylate, isocyanuric acid EO-modified tri (meth) acrylate, trime Roll propane PO modified tri (meth) acrylate, trimethylolpropane EO modified tri (meth) acrylate, ditrimethylolpropane tetra (meth) acrylate, dipentaerythritol hexa (meth) acrylate, 1,6-hexanediol di (meth) acrylate And polyfunctional compounds such as neopentyl glycol di (meth) acrylate and reaction products such as (meth) allylate (for example, poly (meth) acrylate ester of polyhydric alcohol).
Moreover, the urethane (meth) acrylate and polyester (meth) acrylate which have two or more unsaturated bonds are also mentioned.

As the ionizing radiation curable resin, in addition to the above compound, a relatively low molecular weight polyester resin having an unsaturated double bond, polyether resin, acrylic resin, epoxy resin, urethane resin, alkyd resin, spiroacetal resin, Polybutadiene resin, polythiol polyene resin, and the like can also be used as the ionizing radiation curable resin.

When the ionizing radiation curable resin is used as an ultraviolet curable resin, the coating liquid preferably contains a photopolymerization initiator.
Specific examples of the photopolymerization initiator include acetophenones, benzophenones, Michler benzoylbenzoate, α-amyloxime esters, thioxanthones, propiophenones, benzyls, benzoins, and acylphosphine oxides. It is done. Further, it is preferable to use a mixture of photosensitizers, and specific examples thereof include n-butylamine, triethylamine, poly-n-butylphosphine and the like.

As the photopolymerization initiator, acetophenones, benzophenones, thioxanthones, benzoin, benzoin methyl ether, etc. are used alone or in combination when the ultraviolet curable resin is a resin system having a radical polymerizable unsaturated group. It is preferable. When the ultraviolet curable resin is a resin system having a cationic polymerizable functional group, the photopolymerization initiator includes aromatic diazonium salt, aromatic sulfonium salt, aromatic iodonium salt, metallocene compound, benzoin sulfonic acid. It is preferable to use esters or the like alone or as a mixture.
The addition amount of the photopolymerization initiator is preferably 0.1 to 10 parts by mass with respect to 100 parts by mass of the ultraviolet curable resin.

The ionizing radiation curable resin is used in combination with a solvent-drying resin (a thermoplastic resin or the like, which is a resin that forms a film only by drying the solvent added to adjust the solid content during coating). You can also In this case, the solvent-drying resin plays an additive role, and an ionizing radiation curable resin is mainly used. The addition amount of the solvent-drying resin is preferably 40% by mass or less based on the total solid content of the resin component contained in the coating liquid.
Examples of the solvent-drying resin include thermoplastic resins. As the thermoplastic resin, those generally exemplified are used. By adding the solvent-drying resin, coating film defects on the coated surface can be effectively prevented.
Specific examples of preferable thermoplastic resins include, for example, styrene resins, (meth) acrylic resins, vinyl acetate resins, vinyl ether resins, halogen-containing resins, alicyclic olefin resins, polycarbonate resins, and polyester resins. , Polyamide resins, cellulose derivatives, silicone resins, and rubbers or elastomers.
As the thermoplastic resin, it is usually preferable to use a resin that is non-crystalline and soluble in an organic solvent (particularly a common solvent capable of dissolving a plurality of polymers and curable compounds). In particular, resins with high moldability or film formability, transparency and weather resistance, such as styrene resins, (meth) acrylic resins, alicyclic olefin resins, polyester resins, cellulose derivatives (cellulose esters, etc.) Etc. are preferred.

According to a preferred embodiment of the present invention, when the material of the light-transmitting substrate is a cellulose resin such as triacetyl cellulose “TAC”, as a preferred specific example of the thermoplastic resin, a cellulose resin such as nitrocellulose, Examples include acetyl cellulose, cellulose acetate propionate, and ethyl hydroxyethyl cellulose. By using the cellulose resin, the adhesion and transparency between the light-transmitting substrate and the diffusion layer can be improved.

The coating liquid may further contain a thermosetting resin. Examples of the thermosetting resin include phenol resin, urea resin, diallyl phthalate resin, melanin resin, guanamine resin, unsaturated polyester resin, polyurethane resin, epoxy resin, aminoalkyd resin, melamine-urea cocondensation resin, silicon resin. And polysiloxane resin. When a thermosetting resin is used, a curing agent such as a crosslinking agent and a polymerization initiator, a polymerization accelerator, a solvent, a viscosity modifier, and the like can be used in combination as necessary.

In the antiglare film of the present invention, the refractive index of the radiation-curable binder, a difference between the refractive index of the fine particles (A) and organic fine particles (B), when the respective delta _A and delta _B, the delta _A and delta _B, it is preferable to satisfy the following formula (1).
| Δ _B | <| Δ _A | (1)
By satisfying the above formula (1), there is no surface glare that has both internal diffusion with a small diffusion angle due to organic fine particles (B) and internal diffusion with a large diffusion angle due to fine particles (A), and excellent prevention of screen luminance uniformity. A dazzling film can be obtained.
The refractive index of the radiation curable binder, fine particles (A) and organic fine particles (B) can be measured by any method. For example, the Becke method, the minimum deviation method, the deviation analysis, the mode It can be measured by the line method, ellipsometry method or the like.
Further, when the radiation curable binder contains the (meth) acrylate and other resins, the refractive index of the radiation curable binder is the refractive index of all the resin components contained excluding fine particles. To tell.
As a preferable method for measuring the refractive index, in the case of a radiation curable binder, there is a method in which only the binder portion is removed from the cured film and measured by the Becke method. Further, the refractive index difference between the organic fine particles and the resin component can be measured by measuring the phase difference using a transmission type phase shift laser micro interference device PLM-OPT manufactured by NTT Advanced Technology. Therefore, the method of obtaining the refractive index of the organic fine particles in the form of the refractive index ± refractive index difference of the resin component obtained previously can be mentioned.

The coating liquid preferably further contains a solvent.
The solvent is not particularly limited. For example, water, alcohol (eg, methanol, ethanol, isopropanol, butanol, benzyl alcohol), ketone (eg, acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, cyclopentanone), ester ( Examples, methyl acetate, ethyl acetate, propyl acetate, butyl acetate, methyl formate, ethyl formate, propyl formate, butyl formate), aliphatic hydrocarbons (eg, hexane, cyclohexane), halogenated hydrocarbons (eg, methylene chloride, chloroform) , Carbon tetrachloride), aromatic hydrocarbons (eg, benzene, toluene, xylene), amides (eg, dimethylformamide, dimethylacetamide, n-methylpyrrolidone), ethers (eg, diethyl ether, dioxane, tetrahydrophenol) Emissions), ether alcohols (e.g., 1-methoxy-2-propanol) and the like.

In the antiglare film of the present invention, the radiation curable binder and the solvent may be selected from those having the property of swelling the organic fine particles (B), but only one of them may be used. Those having the property of swelling the organic fine particles (B) may be selected and used.
In addition, since the formation of the impregnated layer of the organic fine particles (B) can be performed more reliably regardless of the degree of swelling of the radiation curable binder because of the presence of a solvent having a swelling property, It is more preferable that at least the solvent has a property of swelling the organic fine particles (B). This is because the organic fine particles (B) are first swelled by the action of the solvent, and then the low molecular weight components contained in the radiation curable binder are impregnated. Analogy.
In the antiglare film of the present invention, the combination of the radiation curable binder and the solvent is a (meth) acrylate monomer and the organic solvent as the solvent because the molecular weight is small and the impregnation is easy. A combination with a ketone or ester having a strong property of swelling the fine particles (B) is preferable.
Moreover, the amount of impregnation of the low molecular weight component contained in the radiation-curable binder can be controlled by adjusting the degree of swelling of the organic fine particles (B) by mixing the solvent.
When cellulose triacetate (hereinafter also referred to as a TAC substrate) is used as the light-transmitting substrate, the above-mentioned for preventing interference fringes generated at the interface and the interface of the diffusion layer to the light-transmitting substrate. It is preferable to use a solvent that can swell the TAC substrate and impregnate the TAC substrate with the low molecular weight component in the solvent and the resin component. It is more preferable that the solvent used for swelling the organic fine particles (B) and the solvent that impregnates the TAC substrate are common. That is, when the solvent for the TAC substrate and the solvent used for preparing the organic fine particles (B) having the impregnated layer in advance are almost the same, the balance of the compound contained in the coating liquid becomes very stable. In addition, an excellent coating liquid that can be stably processed even when an antiglare film is processed for a long time can be obtained.
Preferable as such a solvent is methyl isobutyl ketone. Also preferred as the low molecular weight component in the resin component are pentaerythritol tri (meth) acrylate, pentaerythritol penta (meth) acrylate, dipentaerythritol penta (meth) acrylate, dipentaerythritol hexa (meth) acrylate and the like. .

Moreover, it is preferable that the said coating liquid contains a layered inorganic compound. The diffusion layer to be formed contains the above layered inorganic compound, and the hard coat property, curl prevention property, ultraviolet resistance, crack prevention property and the like of the diffusion layer can be improved. Moreover, the aggregate of the fine particles (A) described above can be suitably formed. Further, when the organic fine particles (B) are contained, the fine particles (A) can be suitably aggregated and aggregation of the fine particles (A) and the organic fine particles (B) can be prevented.
As the layered inorganic compound, in order to maintain the transparency of the antiglare film of the present invention, the particle diameter D50 (laser diffraction method) is preferably 0.3 to 5.0 μm, more preferably 0.5. It is about 3.0 μm. Since the layered inorganic compound is a plate-like particle, D50 is used for the particle diameter. For example, when talc having a D50 of 0.6 μm is used, when the cross-sectional SEM observation of the diffusion layer is performed, the major axis is roughly large. It appears to be about 0.6 μm in part of the particles.

The layered inorganic compound is not particularly limited. Examples include margarite, muscovite, phlogopite, tetrasilic mica, teniolite, antigolite, chlorite, cookite, and nanthite. These layered inorganic fine particles may be natural products or synthetic products.
Among these, as the layered inorganic compound, inorganic compounds containing Si, Al, Mg, and O elements are preferable, and talc is preferable as a compound containing such elements.
By containing talc as the layered inorganic compound, for example, when cross-linked acrylic beads are used as the organic fine particles (B) and styrene is used as the fine particles (A), aggregates of the fine particles (A) described above in the diffusion layer It is possible to suitably control the formation of the organic particles, the aggregation of the organic fine particles (B) in the diffusion layer, and the prevention of the aggregation of the fine particles (A) and the organic fine particles (B). As a result, the resulting antiglare film can attain a high level of antiglare properties, white-browning prevention properties, and surface glare prevention properties.
This is presumed to be due to the fact that the talc is a highly lipophilic substance. That is, since the fine particles (A) (styrene) have lipophilic properties and the organic fine particles (B) (crosslinked acrylic resin) have hydrophilic properties, both fine particles are aggregated by the highly lipophilic talc. I guess that.
In addition, the said layered inorganic compound means the inorganic compound used as a layered structure, and includes what looks like a needle shape or a fiber shape in cross-sectional microscope observation.
In addition, since the copolymer fine particles of acryl-styrene can easily have appropriate hydrophilicity or lipophilicity by changing the ratio of the highly hydrophilic acrylic component and the highly lipophilic styrene component, the layered inorganic It can be easily performed to exhibit the aggregation performance by the compound.

When the coating film contains the layered inorganic compound, the content may be adjusted to exceed 1 part by weight and 40 parts by weight or less with respect to 100 parts by weight of the radiation curable binder. preferable. If the amount is 1 part by mass or less, the effect of containing the layered inorganic compound may not be sufficiently obtained. If the amount exceeds 40 parts by mass, the viscosity of the coating liquid becomes too high, and thus the antiglare property of the present invention. The smoothness of the surface of the film cannot be obtained, resulting in poor optical characteristics, and the viscosity of the coating solution may become too high to be applied. The minimum with more preferable content of the said layered inorganic compound is 2 mass parts, and a more preferable upper limit is 30 mass parts. By being in this range, it is possible to ensure the preferable aggregation and inclination angle of the fine particles.

The said coating liquid can be prepared by mixing each material mentioned above.
A method for preparing the coating liquid by mixing the above materials is not particularly limited, and for example, a paint shaker or a bead mill may be used.

The said diffusion layer can be formed by apply | coating the said coating liquid on the at least one surface of the said translucent base material, drying, forming a coating film, and hardening this coating film.
The method for applying the coating liquid is not particularly limited, and examples thereof include a roll coating method, a Miya bar coating method, a gravure coating method, and a die coating method.

The thickness of the coating film formed by applying the coating liquid is not particularly limited, and is appropriately determined in consideration of the uneven shape formed on the surface, the material used, and the like. The dry film thickness is preferably about 1 to 20 μm, and more preferably 2 to 15 μm. This is because if the film thickness is less than 1 μm, the hard coat property is inferior, and if it exceeds 20 μm, curls and cracks are likely to occur.
The thickness of the diffusion layer can be measured by, for example, cross-sectional SEM observation of the diffusion layer. In the measurement, the thickness from the diffusion layer surface position where the organic fine particles (A2) are not present to the light transmissive substrate interface is measured at 5 points or more, and the average value is obtained.

Here, in the antiglare film of the present invention, the fine particles (A) in the diffusion layer form the two aggregates described above.
Such an aggregate can be formed by the following method, for example, when the coating liquid contains a layered inorganic compound.
That is, first, the type and amount of a layered inorganic compound (for example, talc) suitable for agglomeration of the two fine particles (A) depending on the degree of hydrophilicity / hydrophobicity are determined by checking in advance.
Subsequently, the determined layered inorganic compound is mixed with the coating liquid together with the fine particles (A) and the like, and the coating film formed using the coating liquid is set to the above-described film thickness range.
The reason why the aggregate can be formed by such a method is not clear, but in the coating film, it is affected by the difference in lipophilicity or surface tension between the light-transmitting substrate on the lower surface and the air layer on the upper surface. Analogy with things.

As described above, the organic fine particles (B) having an impregnated layer are formed by swelling the organic fine particles (B) with the radiation curable binder and / or solvent and impregnating the radiation curable binder. However, the preparation of the organic fine particles (B) having the impregnated layer may be performed in the coating liquid, and in the coating film formed by applying to the light-transmitting substrate. May be performed.

The diffusion layer can be formed by curing the coating film formed on the light transmissive substrate.
Although it does not specifically limit as a hardening method of the said coating film, It is preferable to carry out by ultraviolet irradiation. When curing by ultraviolet rays, it is preferable to use ultraviolet rays having a wavelength range of 190 to 380 nm. Curing with ultraviolet rays can be performed, for example, with a metal halide lamp, a high-pressure mercury lamp, a low-pressure mercury lamp, an ultrahigh-pressure mercury lamp, a carbon arc lamp, a black light fluorescent lamp, or the like. Specific examples of the electron beam source include various electron beam accelerators such as a cockcroft-wald type, a bandegraft type, a resonant transformer type, an insulating core transformer type, a linear type, a dynamitron type, and a high frequency type.

In the antiglare film of the present invention, the diffusion layer has an uneven shape on the surface.
The concavo-convex shape on the surface of the diffusion layer preferably has a convex portion (hereinafter also referred to as a convex portion (A)) at a position corresponding to the above-mentioned aggregate of fine particles (A) in the diffusion layer.
Since the convex part (A) formed on the surface of the diffusion layer is formed by the above-mentioned aggregate, it can be made higher than the particle size, so that it exhibits sufficient anti-glare performance and particles. Are present obliquely, and the area of the particles irradiated with external light is reduced and reflection at the interface with the binder is reduced as compared with the case where they are arranged in parallel. Further, since it is not necessary to increase the thickness of the diffusion layer, it is possible to suitably prevent the anti-glare film of the present invention from being curled or cracking in the diffusion layer.

Further, when the diffusion layer contains the organic fine particles (B) having the above-described impregnation layer, convex portions (hereinafter referred to as convex portions (B)) formed at positions corresponding to the organic fine particles (B) of the diffusion layer. The height corresponds to the organic fine particles (C) on the surface of the diffusion layer (C) containing the organic fine particles (C) satisfying all the following requirements (1), (2) and (3). It is preferable that the height is lower than the height of the convex portion (hereinafter also referred to as the convex portion (C)).
Requirement (1): Requirement (2) for forming the diffusion layer (C) under the same conditions as the diffusion layer containing the organic fine particles (B) except that the organic fine particles (C) are used instead of the organic fine particles (B). : The organic fine particles (C) in the diffusion layer (C) have the same average particle size as the organic fine particles (B) in the diffusion layer (3): The organic fine particles (C) are in the diffusion layer (C) No impregnated layer is formed

The convex part (B) at a position corresponding to the organic fine particles (B) of the diffusion layer has a gentle shape with a lower height and / or average inclination angle than the convex part (C). The antiglare film of the present invention having such a diffusion layer on which the convex portion (B) is formed can be further improved in antiglare property and anti-glare property.
This is presumably because the organic fine particles (B) in the diffusion layer are very flexible as compared with the organic fine particles (C). That is, when the coating film is cured, the radiation curable binder causes curing shrinkage, but the curing shrinkage of the surface where the organic fine particles (B) are located is the shrinkage of the surface where the organic fine particles (B) are not located. In comparison, the amount of the radiation curable binder is small, so it becomes small. However, since the organic fine particles (B) are very flexible fine particles, the organic fine particles (B) are deformed by curing shrinkage of the coating film. As a result, the height and / or average inclination angle of the formed convex part (B) is compared with the convex part (C) formed on the surface of the diffusion layer (C) containing the harder organic fine particles (C). I guess it will be low and smooth.
The height of the convex portion is the difference between the height of the convex portion existing on the surface and the concave portion between the convex portion adjacent to the convex portion when the antiglare film surface is observed by AFM. It is measured as the height n of the convex part (n is 1 to 10). And it calculates | requires by averaging 10 points | pieces of arbitrary convex part height calculated | required in this way.

In the antiglare film of the present invention, the fine particles (A) in the diffusion layer form two aggregates at a predetermined ratio, and the two fine particles (A) in the aggregates are light-transmitting groups. With respect to the surface of the material, the straight lines connecting the centers thereof are aggregated so as to form an inclination angle. For this reason, the antiglare film of the present invention can have a convex portion formed at a position corresponding to the aggregate of the fine particles (A) on the surface thereof to an appropriate height, and is excellent in antiglare property, Generation of white brown can be sufficiently suppressed, and generation of surface glare can be suitably prevented. Moreover, since it is not necessary to thicken the said diffusion layer, it can prevent suitably that a curl and a crack arise in a diffusion layer in the anti-glare film of this invention.
Furthermore, when the said diffusion layer contains the organic fine particle (B) which has the impregnation layer mentioned above, the anti-glare film of this invention is the organic fine particle (B) in this diffusion layer, and the hardened | cured material of a radiation-curable binder. The adhesion is extremely excellent. In addition, it is preferable that the anti-glare film of the present invention does not cause cracks in a mandrel test under the condition that the mandrel diameter is 10 mm, more preferably 8 mm, and even more preferably 6 mm.
Further, when the impregnation layer is formed on the organic fine particles (B) in the diffusion layer, the impregnation layer is formed in a state in which a radiation curable binder is mixed. The refractive index of the organic fine particles (B) (impregnated layer) in the diffusion layer and the cured product of the radiation curable binder is reduced, and reflection at the interface can be suitably reduced. At the same time, the impregnated layer has an appropriate layer thickness, and the center of the organic fine particles (B) maintains the refractive index of the initial organic fine particles (B). It is possible to prevent surface glare.
Furthermore, the convex part formed in the position corresponding to the organic fine particles (B) of the diffusion layer can be formed into a gentle shape with a low height. For this reason, the antiglare property, the anti-glare property and the anti-glare property of the antiglare film of the present invention can be achieved at a higher level.

The method for producing such an antiglare film of the present invention is also one of the present invention.
That is, the method for producing an antiglare film of the present invention includes an antiglare film having a light-transmitting substrate and a diffusion layer formed on at least one surface of the light-transmitting substrate and having an uneven shape on the surface. A coating film containing a radiation curable binder containing fine particles (A) and (meth) acrylate monomers as essential components on at least one surface of the light transmissive substrate. , Drying to form a coating film, curing the coating film to form the diffusion layer, and the fine particles (A) in the diffusion layer have a straight line connecting the centers of 50% or more. Aggregates aggregated so as to form an inclination angle with respect to the surface of the light transmissive substrate are formed.

In the method for producing an antiglare film of the present invention, examples of the material constituting the coating liquid are the same as those described in the above-described antiglare film of the present invention.
Moreover, the process similar to the method demonstrated in the anti-glare film of this invention mentioned above as the process of forming the said diffused layer is mentioned.

Also provided is a polarizing plate comprising a polarizing element, comprising the antiglare film of the present invention by bonding a light-transmitting substrate to the surface of the polarizing element. It is one of the inventions.

The polarizing element is not particularly limited, and for example, a polyvinyl alcohol film, a polyvinyl formal film, a polyvinyl acetal film, an ethylene-vinyl acetate copolymer saponified film, which is dyed with iodine or the like and stretched can be used. In the laminating process of the polarizing element and the antiglare film of the present invention, it is preferable to saponify the light-transmitting substrate. By the saponification treatment, the adhesiveness is improved and an antistatic effect can be obtained.

This invention is also an image display apparatus provided with the said anti-glare film or the said polarizing plate on the outermost surface. Examples of the image display device include LCD, PDP, FED, ELD (organic EL, inorganic EL), CRT, touch panel, and electronic paper.

The LCD includes a transmissive display body and a light source device that irradiates the transmissive display body from the back. When the image display device of the present invention is an LCD, the antiglare film of the present invention or the polarizing plate of the present invention is formed on the surface of the transmissive display.

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

The PDP includes a front glass substrate and a rear glass substrate disposed with a discharge gas sealed between the front glass substrate and the front glass substrate. When the image display device of the present invention is a PDP, the surface of the surface glass substrate or the front plate (glass substrate or film substrate) is provided with the above-described antiglare film.

Other image display devices include zinc sulfide and diamine substances that emit light when a voltage is applied: an ELD device that emits light on a glass substrate, controls the voltage applied to the substrate, and displays electrical signals as light. It may be an image display device such as a CRT that generates an image visible to human eyes. In this case, the antiglare film described above is provided on the outermost surface of each display device as described above or the surface of the front plate.

In any case, the antiglare film of the present invention can be used for display displays of televisions, computers and the like. In particular, it can be suitably used for the surface of high-definition image displays such as CRT, liquid crystal panel, PDP, ELD, touch panel, and electronic paper.

In the antiglare film of the present invention, the fine particles (A) in the diffusion layer form two aggregates at a predetermined ratio, and the two fine particles (A) in the aggregates are light-transmitting groups. With respect to the surface of the material, the straight lines connecting the centers thereof are aggregated so as to form an inclination angle. For this reason, the antiglare film of the present invention can have a convex portion formed at a position corresponding to the aggregate of the fine particles (A) on the surface thereof to an appropriate height, and is excellent in antiglare property, Since the particles exist at an angle, the area of the particles irradiated with external light is reduced and reflection at the interface with the binder is reduced compared to the case where they are arranged in parallel. Further, the contrast is high, the generation of surface glare can be suitably prevented, and the hard coat property is also provided. Moreover, since it is not necessary to thicken the said diffusion layer, it can prevent suitably that a curl and a crack arise in a diffusion layer in the anti-glare film of this invention.

It is sectional drawing which shows typically the state of the aggregate in the diffusion layer of the anti-glare film of this invention. 4 is a cross-sectional SEM photograph showing an aggregate in which two fine particles (A) in the diffusion layer of the antiglare film according to Example 1 are aggregated. 4 is a cross-sectional SEM photograph of a diffusion layer of an antiglare film according to Example 2. 4 is a cross-sectional SEM photograph of a diffusion layer of an antiglare film according to Example 3.

The contents of the present invention will be described by the following examples, but the contents of the present invention should not be construed as being limited to these examples.

Example 1
First, triacetyl cellulose (manufactured by Fuji Film Co., Ltd., thickness 80 μm) was prepared as a light transmissive substrate.
Next, as a radiation curable binder, a mixture of pentaerythritol triacrylate (PETA), dipentaerythritol hexaacrylate (DPHA), and polymethyl methacrylate (PMMA) (mass ratio; PETA / DPHA / PMMA = 86/5/9) ) (Refractive index 1.51), 1-hydroxy-cyclohexyl-phenyl-ketone: Irgacure 184 (manufactured by BASF) as a photopolymerization initiator (5 parts by mass with respect to 100 parts by mass of binder solid content), As the fine particles (A), highly crosslinked polystyrene particles (refractive index 1.59, average particle size 4.0 μm) are 12.0 parts by mass with respect to 100 parts by mass of the radiation curable binder, and talc particles as a layered inorganic compound. (Refractive index 1.57, average particle diameter D50; 0.8 μm) Against over 100 parts by weight it was contained 20.0 parts by weight. A coating solution was prepared by blending 190 parts by mass of a mixture of toluene and methyl isobutyl ketone (mass ratio 8: 2) as a solvent with respect to 100 parts by mass of the radiation curable binder.
The obtained coating liquid was allowed to stand for 24 hours, and then applied to a light-transmitting substrate by a gravure method, and dried at a flow rate of 1.2 m / s through 70 ° C. and dried for 1 minute. A film was formed.
Thereafter, the coating film was irradiated with ultraviolet rays (200 mJ / cm ^{2 in a} nitrogen atmosphere) to cure the radiation curable binder to form a diffusion layer, and an antiglare film was produced. The thickness of the diffusion layer was 6.6 μm.

(Examples 2 to 7, Comparative Examples 1 to 9, Reference Example 1)
An antiglare film was produced in the same manner as in Example 1 except that each component added to the coating liquid and the thickness of the diffusion layer to be formed were as shown in Table 1.

In Table 1, details of symbols shown in the fine particles (A), the organic fine particles (B), the radiation curable binder, and the layered inorganic compound are as follows. In Table 1, the content of the fine particles (A), the organic fine particles (B), and the layered inorganic compound indicates the content (parts by mass) relative to 100 parts by mass of the radiation curable binder.

(Fine particle A)
A: Highly crosslinked polystyrene particles (refractive index 1.59, average particle size 4.0 μm, manufactured by Soken Chemical Co., Ltd.)
B: Highly cross-linked acrylic-polystyrene particles (refractive index 1.57, average particle size 3.5 μm, manufactured by Soken Chemical Co., Ltd.)
C: Highly cross-linked polystyrene particles (refractive index 1.59, average particle size 2.0 μm, manufactured by Soken Chemical Co., Ltd.)
D: Highly crosslinked polystyrene particles (refractive index 1.59, average particle size 9.0 μm, manufactured by Soken Chemical Co., Ltd.)

(Organic fine particle B)
E: Low cross-linked acrylic particles (refractive index 1.49, average particle size 5.0 μm, manufactured by Soken Chemical Co., Ltd.)

(Layered inorganic compound)
M: Talc (refractive index 1.57, average particle size 0.8 μm, manufactured by Nippon Talc)
N: Bentonite (refractive index 1.52, average particle size 0.5 μm, manufactured by Hojun Co.)

(Radiation curable binder)
P: A mixture of pentaerythritol triacrylate (PETA), dipentaerythritol hexaacrylate (DPHA), and polymethyl methacrylate (PMMA) (mass ratio; PETA / DPHA / PMMA = 86/5/9) (refractive index 1 .51)
Q: Pentaerythritol triacrylate (PETA) (refractive index 1.51)
R: Mixture of 60 parts of vinyl acetate resin and 40 parts of methyl methacrylate resin (refractive index 1.47)

The following evaluation was performed about the anti-glare film obtained by the Example and the comparative example. The results are shown in Table 2.

(Measurement of aggregates)
The antiglare films obtained in Examples, Comparative Examples, and Reference Examples were cut in the thickness direction, and 20 fine particles (A) were randomly observed with a cross-sectional SEM. The ratio of the aggregates formed so that the straight line connecting the centers of the films formed an inclination angle of 20 to 70 ° with respect to the surface of the light-transmitting substrate was calculated.

(Measurement of tilt angle of aggregates)
The anti-glare films obtained in Examples, Comparative Examples and Reference Examples were cut in the thickness direction, and 20 fine particles (A) were randomly observed with a cross-sectional SEM, and two fine particles (A) were aggregated. For the aggregates, the average value of the inclination angles formed by the straight lines connecting the centers of the aggregates with respect to the surface of the light-transmitting substrate was measured and evaluated according to the following criteria.
○: The average value of the inclination angle is in the range of 30 to 60 ° Δ: The average value of the inclination angle is out of the range of 30 to 60 °, but is in the range of 20 to 70 ° ×: The average value of the inclination angle is 2 out of the range of 20 to 70 ° is a cross-sectional SEM photograph of an aggregate in which two fine particles (A) in the diffusion layer of the antiglare film according to Example 1 are aggregated.

(Thickness of impregnated layer of organic fine particles (B))
The antiglare film containing organic fine particles (B) in the diffusion layer is cut in the thickness direction, and the thickness of the impregnated layer formed on the cross section of the five organic fine particles (B) is determined by SEM observation of the cross section. Each of the two points was measured for a total of 10 points, and the average value was calculated.
3 shows one of the cross-sectional SEM photographs of the diffusion layer of the antiglare film according to Example 2, and FIG. 4 shows one of the cross-sectional SEM photographs of the diffusion layer of the antiglare film according to Example 3. Indicated.

(contrast)
The antiglare films obtained in Examples, Comparative Examples and Reference Examples were bonded to a black acrylic plate using a transparent adhesive film for an optical film, and the surface condition of the antiglare film was determined by 15 subjects. Visual sensory evaluation was performed from various directions under bright room conditions of 1000 Lx. It was determined whether or not glossy black color could be reproduced, and evaluated according to the following criteria.
◎: 10 or more people who answered good ○: 9-8 people who answered good △: 7-5 people who answered good ×: 4 or less people who answered good

(Anti-glare and surface glare evaluation)
The polarizing plate on the outermost surface of the liquid crystal television “KDL-40X2500” manufactured by Sony Corporation was peeled off, and a polarizing plate without surface coating was attached.
Next, the anti-glare film obtained in Examples, Comparative Examples and Reference Examples is further coated with the transparent adhesive film for optical film (total light transmittance of 91% or more, haze 0 so that the diffusion layer side is the outermost surface. 3% or less and a film thickness of 20 to 50 μm, for example, MHM series (manufactured by Nichiei Kako Co., Ltd.).
The LCD TV was installed in a room with an illuminance of about 1000 Lx, displayed on a white screen, and 15 subjects from various angles up and down and left and right from a location about 1.5 to 2.0 m away from the LCD TV. However, visual sensory evaluation was performed on the antiglare property and surface glare, respectively. Evaluation was made according to the following criteria.
◎: 10 or more people who answered good ○: 9-8 people who answered good △: 7-5 people who answered good ×: 4 or less people who answered good

(Hard coat property)
The pencil hardness test was performed on the surface of the antiglare film according to Examples, Comparative Examples, and Reference Examples according to JIS K5600-5-4 (1999) by drawing five lines at a load of 750 g and 3H.
○: No more than 2 scratches in 3H pencil hardness test Δ: 3-4 scratches in 3H pencil hardness test ×: 5 scratches in 3H pencil hardness test

As shown in Table 2, the antiglare films according to Examples 1, 2, 4 and 7 were all good in contrast, antiglare properties, surface glare and hard coat properties.
The antiglare film according to Example 3 was inferior in surface glare evaluation because the inclination angle of the fine particles (A) was in the range of 60 to 70 °, and the antiglare film according to Example 5 was a layered inorganic compound. The antiglare film according to Example 6 has a considerably higher content of the layered inorganic compound than that of Example 1 and the like. Since the viscosity of the liquid was high and the surface smoothness of the antiglare film was inferior, the evaluation of contrast, antiglare property and surface glare was inferior, but all were results that could be judged as good overall.
On the other hand, none of the antiglare films according to the comparative examples had good contrast, antiglare properties, surface glare, and hard coat properties.
Moreover, since the average particle diameter of the organic fine particles (B) was not less than the thickness of the diffusion layer, the antiglare film according to Reference Example 1 was inferior in contrast and hard coat properties.

The antiglare film of the present invention is suitable for displays such as cathode ray tube display (CRT), liquid crystal display (LCD), plasma display (PDP), electroluminescence display (ELD), touch panel, electronic paper, especially high definition display. It can be preferably used.

DESCRIPTION OF SYMBOLS 10 Anti-glare film 11 Light transmissive base material 12 Diffusion layer 13 Fine particle (A)

Claims (15)

1. An anti-glare film having a light-transmitting substrate and a diffusion layer formed on at least one surface of the light-transmitting substrate and having an uneven shape on the surface,
   The diffusion layer is formed by applying a coating liquid containing fine particles (A) and a radiation curable binder containing a (meth) acrylate monomer as essential components onto at least one surface of the light-transmitting substrate, and then drying. To form a coating film, and to cure the coating film,
   The fine particles (A) in the diffusion layer form two aggregates in which 50% or more of the particles are aggregated so that a straight line connecting the centers thereof forms an inclination angle with respect to the surface of the light-transmitting substrate. An anti-glare film characterized by
2. 2. The inclination angle formed by a straight line connecting the centers of the two fine particles (A) forming the aggregate and the surface of the light-transmitting substrate is 20 to 70 °. Antiglare film.
3. The antiglare film according to claim 1 or 2, wherein the coating liquid further contains a layered inorganic compound.
4. The antiglare film according to claim 3, wherein the layered inorganic compound is talc.
5. 5. The antiglare film according to claim 3, wherein the content of the layered inorganic compound is 2 to 40 parts by mass with respect to 100 parts by mass of the radiation curable binder.
6. 6. The antiglare film according to claim 1, wherein the fine particles (A) are polystyrene fine particles and / or acrylic-styrene copolymer fine particles.
7. When the average particle diameter of the fine particles (A) was _{D A,} the _{D A} is claim 1, 2, 3 and satisfies the thickness T of the diffusion layer, the following equation (A), The antiglare film according to 4, 5 or 6.
   (1.34 × D _A ) <T <(1.94 × D _A ) (A)
8. The coating liquid further contains organic fine particles (B), and the organic fine particles (B) in the diffusion layer have a larger average particle diameter than the fine particles (A) in the diffusion layer. The antiglare film according to 2, 3, 4, 5, 6 or 7.
9. The antiglare film according to claim 8, wherein the organic fine particles (B) in the diffusion layer are not aggregated.
10. The antiglare film according to claim 8 or 9, wherein the coating liquid contains a solvent that swells the organic fine particles (B).
11. 9. The organic fine particles (B) in the diffusion layer have an impregnation layer impregnated with a radiation curable binder, and the average thickness of the impregnation layer is 0.01 to 1.0 μm. , 9 or 10 Antiglare film.
12. When the average particle diameter of the organic fine particles (B) was _{D B,} said _{D B} is claim and satisfies the thickness T of the diffusion layer, the following formula (B) 8, 9, 10 Or 11. The antiglare film according to 11.
    D _B <T (B)
13. A method for producing an antiglare film comprising a light transmissive substrate and a diffusion layer formed on at least one surface of the light transmissive substrate and having an uneven shape on the surface,
    A coating liquid containing a radiation curable binder containing fine particles (A) and (meth) acrylate monomers as essential components is applied onto at least one surface of the light-transmitting substrate and dried to form a coating film. , Having a step of curing the coating film to form the diffusion layer,
    The fine particles (A) in the diffusion layer form an aggregate in which 50% or more of the fine particles (A) are aggregated so that straight lines connecting the centers thereof form an inclination angle with respect to the surface of the light-transmitting substrate. A method for producing an anti-glare film.
14. A polarizing plate comprising a polarizing element,
    A polarizing plate comprising the antiglare film according to claim 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11 or 12 on a surface of the polarizing element.
15. The antiglare film according to claim 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11 or 12 or the polarizing plate according to claim 14 is provided on the outermost surface. An image display device.

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