JP5450171B2 - Optical film, polarizing plate and image display device - Google Patents

Description

  The present invention relates to an optical film, a polarizing plate, and an image display device.

  In various image display devices such as liquid crystal display (LCD), plasma display panel (PDP), electroluminescence display (ELD), and cathode ray tube display (CRT), contrast reduction due to reflection of external light and image reflection In order to prevent this, an optical film such as an antiglare antireflection film is used on the surface of the display. Such an antireflection film suppresses the reflection of an image or reduces the reflectance due to light scattering or interference. Recently, the use of LCDs in office and home environments has been spreading, improving the anti-glare property that prevents indoor fluorescent lights and viewers' images from appearing on the display surface, and further improving the display contrast in bright places. Improvement is required.

  For an optical film having an antiglare property that is inexpensive and can be mass-produced, an antiglare layer having irregularities on the surface by coating a resin containing translucent fine particles on the surface of the transparent support. Is formed.

  As such an optical film, the film thickness of the antiglare layer is larger than the diameter of the translucent fine particles, and a plurality of the translucent fine particles are aggregated in the horizontal and vertical directions of the film to form irregularities of the antiglare layer. Particle aggregation type or particle grounding type in which the film thickness of the anti-glare layer is smaller than the diameter of the light-transmitting fine particles, and the light-transmitting fine particles are arranged in a single layer in the anti-glare layer to form irregularities of the anti-glare layer (for example, Patent Document 1) is known as an optical film.

As described above, translucent fine particles are added to impart antiglare properties to form irregularities on the surface, but depending on the state of the particles in the antiglare layer, the entire film has a steep inclination As a result, the film becomes whitish and the black reproducibility in the screen display may deteriorate. In recent years, liquid crystal displays have become the mainstream of televisions, and this black reproducibility, in particular, black reproducibility with a glossy black feeling (glossy black as wet) has been increasingly demanded.
However, it has been difficult for conventional optical films to satisfy all of the properties such as “black reproducibility”, “antiglare” and “contrast improvement”.
In order to satisfy the antiglare property, the above-mentioned particle aggregation type optical film requires a certain amount of light-transmitting fine particles (amount that allows the light-transmitting fine particles to aggregate to form a large lump). On the other hand, if the amount of light-transmitting fine particles is reduced for improving black reproducibility and contrast, the antiglare property is lost. For this reason, it is difficult to stably produce a film that satisfies the above-mentioned various performances because the width of the amount of translucent fine particles that achieves both black reproducibility and contrast improvement and anti-glare properties is narrow. In addition, when the amount of the light-transmitting fine particles is reduced, the unevenness of a portion (coarse particles) in which a plurality of light-transmitting fine particles are aggregated in the vertical direction becomes a relatively large mountain, causing a problem of being visually recognized as a point defect.
On the other hand, in the latter particle grounding type, the required amount of translucent fine particles for satisfying the antiglare property is less than that in the particle aggregation type, so that it is easy to improve the contrast. Moreover, if the diameter of translucent fine particle is constant, the unevenness | corrugation of an anti-glare layer will be constant and it will become an optical film with few point defects. However, even if the amount of the light-transmitting fine particles is adjusted, it is difficult to adjust the slope of the unevenness because the film thickness of the antiglare layer is thin, and there is a problem that the black reproducibility cannot be improved.

  As a method for achieving both “black reproducibility” and “antiglare property”, Patent Document 2 describes forming a surface adjustment layer on a light diffusion layer having an uneven structure. However, since the film described in Patent Document 2 is such that the thickness of the light diffusion layer is larger than the diameter of the light-transmitting fine particles (particle aggregation type), a portion where the light-transmitting fine particles are aggregated in the vertical direction (coarse) The unevenness of the particles becomes a large mountain, and a problem of being visually recognized as a point defect occurs even after the surface adjustment layer is formed. In addition, since the surface adjustment layer is formed after the light diffusion layer is hardened, the interface between the light diffusion layer and the surface adjustment layer is clearly present, and interference unevenness due to the interface and between the light diffusion layer and the surface adjustment layer are There was a problem that adhesion deteriorated. In addition, in order to apply and dry the light diffusion layer and the surface adjustment layer, respectively, the manufacturing apparatus for coating / drying is passed twice (low productivity), or the manufacturing apparatus is used as a large scale such as coating / drying / coating / drying. There was a need to do.

Japanese Patent No. 4376368 JP 2008-32845 A

An object of the present invention is to provide an optical film that has both good black reproducibility and antiglare property, is free from spot defects due to interference unevenness and coarse particles, is excellent in adhesion of the antiglare layer, and has a good production yield. That is.
Furthermore, another object of the present invention is to provide a polarizing plate and an image display device including the optical film.

  As a result of intensive studies, the present inventors have solved the above problems by the following means.

(1)
An optical film having an antiglare layer containing a binder and translucent fine particles on a support,
The translucent fine particles have an average particle diameter r of 3 μm or more and 15 μm or less,
The content of the translucent fine particles in the antiglare layer is 0.1% by mass or more and 1.0% by mass or less based on the total solid content of the antiglare layer,
The average film thickness of the antiglare layer is larger than the average particle diameter r of the translucent fine particles, and the average distance between the center of the translucent fine particles and the interface of the antiglare layer near the support is h. Then, the average distance h and the average particle diameter r of the translucent fine particles satisfy the following formula 1.
Formula 1: r × 0.5 ≦ h ≦ r × 0.6
(2)
The optical film as described in (1) above, wherein the antiglare layer has an average film thickness of 1.01 to 2.00 times the average particle diameter r of the translucent fine particles.
(3)
(1) or (1) above, wherein an average distance between adjacent translucent fine particles in the antiglare layer is 1.5 to 10 times the average particle diameter r of the translucent fine particles. The optical film as described in 2).
(4)
Any of (1) to (3) above, wherein the antiglare layer further contains inorganic fine particles, and the inorganic fine particles are present on the side far from the support in the film thickness direction of the antiglare layer. The optical film according to one item.
(5)
The optical film as described in (4) above, wherein the inorganic fine particles are inorganic fine particles mainly composed of silica having an average particle diameter of 1 nm to 1 μm.
(6)
The optical film as described in (4) or (5) above, wherein the inorganic fine particles have pores on at least one of the surface and the inside of the particles.
(7)
The optical film according to any one of (4) to (6), wherein the inorganic fine particles are conductive particles.
(8)
The antiglare layer further contains at least one kind of reactive silicone and reactive fluorine compound, and at least one kind of the reactive silicone and reactive fluorine compound is only on the side far from the support in the film thickness direction of the antiglare layer. The optical film as described in any one of (1) to (7) above,
(9)
The surface free energy of the antiglare layer is 30 mN / m or less, The optical film as described in any one of (1) to (8) above.
(10)
The optical film according to any one of (1) to (9) above, wherein a surface refractive index of the antiglare layer is 1.25 or more and 1.49 or less.
(11)
The thickness of the said support body is 15 micrometers or more and 60 micrometers or less, The optical film as described in any one of said (1)-(10) characterized by the above-mentioned.
(12)
The optical film according to any one of (1) to (11) above, further comprising a low refractive index layer on the antiglare layer.
(13)
It is a polarizing plate which has a polarizing film and a protective film on both sides of this polarizing film, Comprising: At least one of this protective film is an optical film as described in any one of said (1)-(12). A polarizing plate characterized by.
(14)
It has an optical film as described in any one of said (1)-(12), or the polarizing plate as described in said (13), The image display apparatus characterized by the above-mentioned.

Moreover, the optical film of the said subject can be provided by the following means.
(15)
A method for producing an optical film having an antiglare layer containing a binder and translucent fine particles on a support,
The optical film is
The translucent fine particles have an average particle diameter r of 3 μm or more and 15 μm or less,
The content of the translucent fine particles in the antiglare layer is 0.1% by mass or more and 1.0% by mass or less based on the total solid content of the antiglare layer,
The average film thickness of the antiglare layer is larger than the average particle diameter r of the translucent fine particles, and the average distance between the center of the translucent fine particles and the interface of the antiglare layer near the support is h. When this is the optical film, the average distance h and the average particle diameter r of the translucent fine particles satisfy the following formula 1.
Formula 1: r × 0.5 ≦ h ≦ r × 0.6
The coating composition (a) containing the light-transmitting fine particles and the binder and the coating composition (b) containing the binder without containing the light-transmitting fine particles are simultaneously coated on the support. And having the step of forming the antiglare layer by curing,
The method for producing an optical film, wherein the coating liquid composition (a) is coated on a side close to the support.
(16)
The optical coating according to (16) above, wherein the coating film composition (a) has an average coating film thickness of 0.10 to 0.70 times the average particle diameter r of the translucent fine particles. A method for producing a film.
(17)
Using a coating apparatus having a backup roller for supporting the support, at least one slot die, and at least one slide-type coating head disposed in the vicinity of the tip of the slot die, The coating composition (a) and the coating composition (b) are simultaneously applied to the support from each of the at least one slot die and the at least one slide-type coating head while being supported by a backup roller. The manufacturing method of the optical film as described in said (15) or (16) to apply | coat.

  According to the present invention, it is possible to provide an optical film with good production yield that has both good black reproducibility and anti-glare properties, is free from spot defects due to interference unevenness and coarse particles, and has excellent adhesion to the anti-glare layer. Can do.

It is a schematic sectional drawing which shows typically an example of the optical film of this invention. It is a schematic sectional drawing which shows typically an example of the optical film of this invention. It is a schematic sectional drawing which shows typically an example of the optical film of this invention. It is a figure which shows typically one Embodiment of a preferable coating device for application | coating of the glare-proof layer of this invention. It is a schematic diagram explaining the outline | summary of the measuring method of an inclination angle. It is a schematic diagram explaining the outline | summary of the measuring method of an inclination angle. It is a schematic diagram explaining the outline | summary of the measuring method of an inclination angle.

  Hereinafter, the present invention will be described in more detail. In the present specification, when a numerical value represents a physical property value, a characteristic value, etc., the description “(numerical value 1) to (numerical value 2)” means “(numerical value 1) or more and (numerical value 2) or less”. . In the present specification, the description “(meth) acrylate” means “at least one of acrylate and methacrylate”. The same applies to “(meth) acrylic acid” and the like.

(Configuration of optical film)
The optical film of the present invention has an antiglare layer containing a binder and translucent fine particles on a support,
The translucent fine particles have an average particle diameter r of 3 μm or more and 15 μm or less,
The content of the translucent fine particles in the antiglare layer is 0.1% by mass or more and 1.0% by mass or less based on the total solid content of the antiglare layer,
The average film thickness of the antiglare layer is larger than the average particle diameter r of the translucent fine particles, and the average distance between the center of the translucent fine particles and the interface of the antiglare layer near the support is h. When the optical film is an optical film, the average distance h and the average particle diameter r of the translucent fine particles satisfy the following formula 1.
Formula 1: r × 0.5 ≦ h ≦ r × 0.6
When the translucent fine particles are indefinite, the shortest distance from the center of the translucent fine particles to the surface of the fine particles is defined as r, and the center of the translucent fine particles is defined as the “center” of the fine particles. Define.

FIG. 1 schematically shows an example of the optical film of the present invention.
As shown in FIG. 1, in one embodiment of the present invention, the optical film 100 has an antiglare layer 102 on a support 101. The antiglare layer 102 has translucent fine particles 103, and unevenness is formed on the surface of the antiglare layer 102. The average film thickness of the antiglare layer 102 is larger than the average particle diameter of the translucent fine particles 103.
The average distance h in the formula 1, in the optical film 100, an average value of the distance h ₁ between the center o and the support 101 of the translucent particles 103. When the average distance h and the average particle diameter (r) of the translucent fine particles 103 satisfy the above formula 1, the translucent fine particles 103 are grounded to the support 101 side interface of the antiglare layer 102, and the translucent fine particles. There is substantially no multi-stage stacking between the layers 103 in the film thickness direction of the antiglare layer 102 (direction perpendicular to the transparent support 101).
With such a configuration, it is possible to obtain good black reproducibility and anti-glare properties, and to suppress the occurrence of point defects due to coarse particles.

As shown in FIG. 1, the antiglare layer in which the translucent fine particles are grounded to the support side interface includes a coating composition (a) containing a binder and the translucent fine particles, and the translucent fine particles containing the binder. It can form by apply | coating the coating composition (b) which does not contain on a support body, and laminating | stacking the layer which consists of each composition.
Hereinafter, in this specification, a layer made of the coating composition (a) is called a layer A, and a layer made of the coating composition (b) is called an overcoat layer.
From the viewpoint of adhesion of the antiglare layer (more specifically, adhesion between the layer A and the overcoat layer) and suppression of interference unevenness, it is preferable that the interface between the layer A and the overcoat layer does not substantially exist. . “The interface is not substantially present” means that the interface between the layer A and the overcoat layer is not clear, and the interface between the two layers cannot be identified even if the cross section is observed with an SEM or an optical microscope after forming both layers. Say. As a means for realizing an antiglare layer substantially free from the interface between the layer A and the overcoat layer, for example, the coating composition (a) and the coating composition (b) are simultaneously coated on the support in a multilayer manner. Thus, it is possible to partially mix the interface between the coating composition (a) and the coating composition (b) during coating and drying. A specific method for producing the antiglare layer will be described later.

FIG. 2 schematically shows an example of an optical film having an antiglare layer including the layer A and an overcoat layer. An optical film 200 shown in FIG. 2 has an antiglare layer 202 having translucent fine particles 203 on a support 201, similarly to the optical film 100 of FIG. The antiglare layer 202 includes a layer A and an overcoat layer B. In FIG. 2, for convenience, the interface between the layer A and the overcoat layer B is indicated by a dotted line. However, as described above, it is preferable that the interface does not substantially exist.
The layer A and the overcoat layer B may have the same composition other than the translucent fine particles 203 or may be different. The antiglare layer 202 may further contain an additive in addition to the binder and the translucent fine particles 203 in order to impart functions other than the antiglare property. In this case, the additive can be present in one of the layer A and the overcoat layer B by including an additive in one of the coating composition (a) and the coating composition (b).
For example, in the present invention, the antiglare layer 202 may include inorganic fine particles, or at least one of reactive silicone and a reactive fluorine compound. These additives are preferably present only on the side far from the support 201 in the film thickness direction of the antiglare layer 202 from the viewpoint of the effect. Here, “the far side” from the support 201 of the antiglare layer 202 refers to the overcoat layer B with respect to the layer A, and the additive is contained only in the coating composition (b). Only the overcoat layer B can be present, that is, on the “far side” from the support 201.

(Layer structure of optical film)
The optical film of the present invention may have a layer other than the layer A and the overcoat layer on the support. As such a layer, for example, a hard coat layer having no light-transmitting fine particles imparting antiglare properties, an antistatic layer, an antireflection layer (low refractive index layer, medium refractive index layer, high refractive index layer, etc.) And antifouling layer. In this invention, it can use suitably as an optical film by having these layers.
Examples of preferred layer structures for the optical film of the present invention are shown below. In each of the following layer configurations, at least “Layer A / Overcoat layer” corresponds to the antiglare layer in the present invention.
Support / Layer A / Overcoat layerSupport / Antistatic layer / Layer A / Overcoat layerSupport / Layer A / Overcoat layer / Low refractive index layerSupport / Layer A / Overcoat layer / Antistatic layer / low refractive index layer / support / hard coat layer / layer A / overcoat layer / low refractive index layer / support / hard coat layer / layer A / overcoat layer / antistatic layer / low refractive index layer Support / Hard coat layer / Antistatic layer / Layer A / Overcoat layer / Low refractive index layerSupport / Layer A / Overcoat layer / High refractive index layer / Low refractive index layerSupport / Layer A / Overcoat layer / Medium refractive index layer / High refractive index layer / Low refractive index layer / Antistatic layer / Support / Layer A / Overcoat layer / Medium refractive index layer / High refractive index layer / Low refractive index layer / Support / Antistatic layer / Layer A / Overcoat layer / Medium refractive index layer / High refractive index layer / Low refractive index layer Antistatic layer / support / layer A / overcoat layer / high refractive index layer / low refractive index layer / high refractive index layer / low refractive index layer

In the present invention, it is also preferable that the layer A has a function of an antistatic layer and the like, and the overcoat layer has a function of an antistatic layer, an antifouling layer, a low refractive index layer and the like at the same time.
In addition, the optical film of the present invention is preferably an antireflection film having a low refractive index layer from the viewpoint of low reflection. Further, an antireflection film comprising a medium refractive index layer / high refractive index layer / low refractive index layer is also preferred. For example, JP-A-8-122504, 8-110401, 10-300902 Configurations described in Japanese Patent Laid-Open No. 2002-243906, Japanese Patent Laid-Open No. 2000-11706, and the like.

Hereinafter, each constituent layer of the optical film of the present invention will be described.
(Anti-glare layer)
The antiglare layer in the optical film of the present invention contains at least a binder and translucent fine particles.
The content of the light-transmitting fine particles in the antiglare layer is 0.1% by mass or more and 1.0% by mass or less with respect to the total solid content of the antiglare layer, and the average film thickness of the antiglare layer is that of the light transmitting fine particles. It is larger than the average particle diameter r. Further, as described above, since the translucent fine particles satisfy the above-described formula 1, substantially all the translucent fine particles are grounded to the interface near the support of the antiglare layer, and the translucent fine particles There is virtually nothing stacked in multiple stages. Here, “substantially all” means that the cross section of the optical film is observed with an optical microscope, 100 translucent fine particles are observed, and 96 or more correspond. By the above, since the unevenness | corrugation which draws a loose arc can be formed in the glare-proof layer surface, black reproducibility and glare-proof property can be made compatible, and generation | occurrence | production of a point defect can be suppressed.

When the content of the light-transmitting fine particles in the antiglare layer is 0.1% by mass or more, irregularities are formed on the surface of the antiglare layer, and good antiglare properties can be obtained. Further, when the content is 1.0% by mass or less, the translucent fine particles are not substantially stacked in multiple stages, and both black reproducibility and antiglare properties can be achieved, and point defects are prevented. be able to. The content of the light-transmitting fine particles in the antiglare layer is preferably 0.1% by mass or more and 0.8% by mass or less, and more preferably 0.2% by mass with respect to the total solid content of the antiglare layer. It is 0.5 mass% or less.
If the average film thickness of the antiglare layer is smaller than the average particle diameter r of the translucent fine particles, the unevenness becomes steep, the film becomes whitish, and it is difficult to obtain good black reproducibility. From the viewpoint of achieving both good black reproducibility and antiglare property, the average film thickness of the antiglare layer is preferably 1.01 to 2.00 times the average particle diameter r of the light-transmitting fine particles. It is more preferably 10 times or more and 1.80 times or less.
Even if the average film thickness of the antiglare layer is larger than the average particle diameter r of the light-transmitting fine particles, the light-transmitting fine particles are stacked in multiple stages if the above-mentioned formula 1 is not satisfied. Further, the surface unevenness of the antiglare layer becomes sharp, and it is impossible to achieve both black reproducibility and antiglare property.
In Formula 1, the average value h of the distance between the center of the light-transmitting fine particles and the interface on the support side of the antiglare layer is 0.50 to 0.60 times the average particle diameter r of the light-transmitting particles. It means that there is. In this case, the translucent fine particles are in contact with the support side interface of the antiglare layer, and there is substantially no multi-stage stacking of the translucent fine particles. Thereby, black reproducibility can be made favorable and point defects can be reduced.
The average particle diameter r of the translucent fine particles and the average distance h between the center of the translucent fine particles and the support side interface of the antiglare layer are obtained by observing the cross section of the optical film with an SEM or an optical microscope. Translucent fine particles can be arbitrarily selected, and for each particle, the particle diameter and the distance between the particle center and the support side interface of the antiglare layer can be measured and calculated as the average value of the 100 particles.

The average distance between adjacent light-transmitting fine particles in the antiglare layer is preferably 1.5 times or more and 10 times or less, and 1.8 times or more and 7.0 times or less the average particle diameter r of the light-transmitting fine particles. It is more preferable that it is 2.0 times or more and 5.0 times or less. The “average distance between adjacent translucent fine particles” referred to here is the distance between the adjacent translucent fine particles in the in-plane direction of the antiglare layer (direction parallel to the support surface) (distance l ₁ shown in FIG. ₁ ). Refers to the average distance. If the distance between the particles is in the above range, the frequency of the light-transmitting fine particles is small, most of the particles are present alone, and the particles are not stacked in multiple stages.
Here, the average distance between adjacent translucent fine particles is determined by observing the optical film under an optical microscope under transmitted light, selecting any 30 translucent fine particles, and for each particle with the closest translucent fine particles. The distance can be measured and calculated as the average value of the 30 particles.

One convex part of the antiglare layer is preferably formed substantially by 3 or less translucent fine particles, and more preferably substantially formed by one translucent fine particle. Here, “substantially 3 or less (or 1)” means that 90% or more of the protrusions of the antiglare layer are 3 or less (or 1) translucent fine particles. Means formed.
As the translucent fine particles, those satisfying the above-mentioned average particle diameter and the value of the internal haze of the optical film described later are preferably used, but the convex portion is substantially formed of one translucent fine particle. Therefore, it is preferable to select particles having good dispersibility.

  The average film thickness of the antiglare layer is preferably 1.8 to 40.5 μm, more preferably 2.8 to 30.8 μm, and still more preferably 3.3 to 27.0 μm. The average film thickness of the antiglare layer can be calculated from an average value obtained by observing the cross section of the optical film of the present invention with an electron microscope and measuring 30 film thicknesses randomly.

(Translucent fine particles)
The refractive index of the translucent fine particles of the present invention is preferably from 1.46 to 1.65, more preferably from 1.47 to 1.60, still more preferably from 1.49 to 1,5, from the viewpoint of imparting internal scattering properties. 1.58.

  In the present invention, the average particle diameter r of the translucent fine particles in the antiglare layer is 3 μm or more and 15 μm or less. The average particle diameter r is preferably 3 μm or more and 10 μm or less, and more preferably 3.5 μm or more and 8 μm or less. If the average particle diameter is less than 3 μm, it is necessary to reduce the film thickness of the antiglare layer and the film hardness is insufficient, which is not preferable. On the other hand, if it exceeds 15 μm, it is necessary to make the film thickness of the antiglare layer considerably thick, which causes problems such as curling and cost increase.

  Specific examples of the light-transmitting fine particles of the present invention include, for example, crosslinked polymethyl methacrylate particles, crosslinked methyl methacrylate-styrene copolymer particles, crosslinked methyl methacrylate-methyl acrylate copolymer particles, and crosslinked acrylate-styrene copolymer particles. Preferred are resin particles such as crosslinked polystyrene particles, crosslinked methyl methacrylate-crosslinked modified acrylate copolymer particles, melamine / formaldehyde resin particles, and benzoguanamine / formaldehyde resin particles. Of these, crosslinked polymethyl methacrylate particles, crosslinked methyl methacrylate-styrene copolymer particles, and the like are preferable.

  As the translucent fine particles of the present invention, one kind may be used, but two or more kinds may be used in combination. When using 2 or more types together, from the viewpoint of improving the durability of the optical film, it is desirable that the refractive index of any two types of translucent fine particles is different. The two or more kinds of translucent fine particles may be either resin particles or inorganic fine particles, respectively. The two or more kinds of translucent fine particles may have the same or different average particle diameter, but the translucent fine particles having the largest average particle diameter have an average film thickness of layer A of the average particle of the translucent fine particles. Those that are 0.10 to 0.70 times the diameter are preferred. In addition, at least one of the two or more kinds of translucent fine particles satisfies the above formula 1. Preferably, the translucent fine particles having the largest average particle diameter satisfy the formula 1, and more preferably all kinds of translucent fine particles satisfy the formula 1.

  When two or more kinds of translucent fine particles are used in combination, one of the two translucent fine particles has a refractive index lower than that of the binder of the antiglare layer (preferably layer A), and the other is less than the binder. It is preferable to take an embodiment with a high refractive index. For example, among the two kinds of translucent fine particles, the high refractive index particles preferably have a refractive index higher by 0.010 to 0.050 than that of the binder, more preferably 0.010 to 0.030 higher. The low refractive index particles are preferably 0.010 to 0.050 lower than the binder, and more preferably 0.010 to 0.030 lower. Since there are two kinds of light-transmitting fine particles having different refractive index differences from the binder, it is easy to control internal scattering and the shape of the surface.

  Here, the refractive index of the binder can be quantitatively evaluated by directly measuring it with an Abbe refractometer or by measuring a spectral reflection spectrum or a spectral ellipsometry. The refractive index of the light-transmitting fine particles is obtained by measuring the turbidity by dispersing an equal amount of the light-transmitting fine particles in a solvent in which the refractive index is changed by changing the mixing ratio of two types of solvents having different refractive indexes. It is measured by measuring the refractive index of the solvent when the turbidity is minimized with an Abbe refractometer.

  When two kinds of translucent fine particles are used, specific examples of one translucent fine particle include those described above. Specific examples of the other translucent fine particles include, for example, crosslinked polymethyl methacrylate particles, crosslinked methyl methacrylate-styrene copolymer particles, crosslinked polystyrene particles, crosslinked methyl methacrylate-methyl acrylate copolymer particles, crosslinked acrylate- Preferred examples include resin particles such as styrene copolymer particles, melamine / formaldehyde resin particles, and benzoguanamine / formaldehyde resin particles. Of these, crosslinked styrene particles, crosslinked polymethyl methacrylate particles, crosslinked methyl methacrylate-styrene copolymer particles and the like are preferable. Furthermore, the surface of these resin particles is a so-called surface-modified particle in which a compound containing fluorine atom, silicon atom, carboxyl group, hydroxyl group, amino group, sulfonic acid group, phosphoric acid group or the like is chemically bonded, or nano-particle such as silica or zirconia. The particle | grains which couple | bonded the size inorganic particle to the surface are also mentioned preferably. Moreover, inorganic fine particles can also be used as the translucent fine particles. Specific examples of the inorganic fine particles include silica particles and alumina particles, and silica particles are particularly preferably used.

  The average particle diameter of the light-transmitting fine particles refers to the primary particle diameter regardless of whether two or more particles are present adjacent to each other in the antiglare layer or independently. . However, agglomerated inorganic particles having a primary particle size of about 0.1 μm are dispersed as secondary particles in the coating solution in a size that satisfies the particle size of the present application, and then applied to the secondary particles. Magnitude.

  As the shape of the translucent fine particles of the present invention, either a true sphere or an indefinite shape can be used. The particle size distribution is preferably monodisperse particles because of the haze value, controllability of diffusibility, and uniformity of the coated surface. For example, when particles having a particle size of 33% or more than the average particle size are defined as coarse particles, the proportion of coarse particles is preferably 1% or less, more preferably 0.8% or less of the total number of particles. Yes, and more preferably 0.4% or less. In this case, even if a low refractive index layer or the like is provided on the antiglare layer, there is no unevenness due to coarse particles, so coating unevenness and repellency due to the unevenness do not occur, and the film thickness of the low refractive index layer becomes uniform. Therefore, an optical film having low reflectance and excellent black reproducibility can be obtained.

  For example, when a particle having a particle size of 16% or more smaller than the average particle size is defined as a fine particle, the proportion of the fine particle is preferably 10% or less of the total number of particles, more preferably 6% or less. Yes, more preferably 4% or less. Particles having such a particle size distribution are obtained by classification after a normal synthesis reaction, and particles having a more preferable distribution can be obtained by increasing the number of classifications or increasing the degree of classification. It is preferable to use a method such as an air classification method, a centrifugal classification method, a sedimentation classification method, a filtration classification method, or an electrostatic classification method for classification.

  The particle size distribution of the particles is measured by a Coulter counter method, and the measured distribution is converted into a particle number distribution. The average particle diameter can be calculated from the obtained particle distribution or measured by a light scattering method or an electron micrograph.

  When translucent fine particles easily settle in the binder, an inorganic filler such as silica may be added to prevent sedimentation. As the amount of the inorganic filler added increases, it is more effective in preventing the sedimentation of the translucent fine particles, but adversely affects the transparency of the coating film. Therefore, preferably, an inorganic filler having a particle size of 0.5 μm or less is contained in an amount of less than 0.1% by mass so as not to impair the transparency of the coating film with respect to the binder.

  Specific examples of translucent fine particles include commercially available resin particles. For example, Chemisnow, MX-300, MX-600, MX-675, MX-1000 manufactured by Soken Chemical Co., Ltd. , RX-0855, MX-800, SX-350HL, SX-713L, MX-1500H, etc., or Sekisui Plastics Co., Ltd. Techpolymer, SSX108HXE, SSX108LXE SSX-106TN, SSX-106FB, XX120S, etc. are used. be able to.

(Preparation of translucent fine particles)
Examples of the method for producing the light-transmitting fine particles according to the present invention include a suspension polymerization method, an emulsion polymerization method, a soap-free emulsion polymerization method, a dispersion polymerization method, a seed polymerization method, and the like. Good. These production methods are described in, for example, “Experimental Methods for Polymer Synthesis” (Takayuki Otsu and Masaaki Kinoshita, Chemical Dojinsha), pages 130 and 146 to 147, “Synthetic Polymers”, Vol. 246-290, 3rd volume, p. 1 to 108, etc., and Japanese Patent Nos. 2543503, 3508304, 2746275, 3521560, 3580320, and Japanese Patent Laid-Open No. 10-1561. Reference can be made to methods described in JP-A No. 7-2908, JP-A No. 5-297506, JP-A No. 2002-145919, and the like.

(binder)
The binder for forming the matrix of the antiglare layer is not particularly limited, but is preferably a polymer having a saturated hydrocarbon chain or a polyether chain as a main chain after curing with ionizing radiation or the like. Moreover, it is preferable that the main binder polymer after hardening has a crosslinked structure.

  In order to obtain a necessary internal scattering property, it is necessary to adjust the refractive indexes of the light-transmitting fine particles and the binder. The absolute value of the refractive index difference between the translucent fine particles and the binder is preferably 0.001 to 0.050, more preferably 0.015 to 0.040, and most preferably 0.010 to 0.030.

  Examples of the polymer having a saturated hydrocarbon chain as a main chain after curing include a polymer of an ethylenically unsaturated monomer. Moreover, as a polymer which has a polyether chain as a principal chain, the polymer by ring-opening of an epoxy-type monomer is preferable. As the binder polymer, a polymer of a mixture of these monomers is also preferable.

  As a polymer of ethylenically unsaturated monomers having a cross-linked structure, a (co) polymer of monomers having two or more ethylenically unsaturated groups is preferable. In order to increase the refractive index, the monomer structure preferably contains at least one selected from an aromatic ring, a halogen atom other than fluorine, a sulfur atom, a phosphorus atom, and a nitrogen atom.

  As the monomer having two or more ethylenically unsaturated groups, specifically, an ester of a polyhydric alcohol and (meth) acrylic acid {for example, ethylene glycol di (meth) acrylate, 1,4-cyclohexanediacrylate , Pentaerythritol tetra (meth) acrylate, pentaerythritol tri (meth) acrylate, trimethylolpropane tri (meth) acrylate, trimethylolethane tri (meth) acrylate, dipentaerythritol tetra (meth) acrylate, dipentaerythritol penta (meth) ) Acrylate, dipentaerythritol hexa (meth) acrylate, pentaerythritol hexa (meth) acrylate, 1,2,3-chlorohexanetetramethacrylate, polyurethane polyacrylate, poly Ester polyacrylate}, vinylbenzene and derivatives thereof (for example, 1,4-divinylbenzene, 4-vinylbenzoic acid-2-acryloylethyl ester, 1,4-divinylcyclohexanone), vinyl sulfone (for example, divinyl sulfone), ( And (meth) acrylamide (for example, methylenebisacrylamide).

Further, a resin having two or more ethylenically unsaturated groups may be included as a monomer. For example, oligomers such as polyfunctional compounds such as relatively low molecular weight polyester resins, polyether resins, acrylic resins, epoxy resins, urethane resins, alkyd resins, spiroacetal resins, polybutadiene resins, polythiol polyene resins and polyhydric alcohols Examples include prepolymers.
Two or more of these monomers may be used in combination, and the monomer having two or more ethylenically unsaturated groups is preferably 10 to 100% of the total monomers forming the binder polymer.

  Polymerization of these monomers having an ethylenically unsaturated group can be carried out by irradiation with ionizing radiation or heating in the presence of a photo radical polymerization initiator or a thermal radical polymerization initiator. Therefore, a coating solution containing a monomer having an ethylenically unsaturated group, a photo radical polymerization initiator or a thermal radical polymerization initiator, and particles, and if necessary, an inorganic filler, a coating aid, other additives, an organic solvent and the like. After coating the coating solution on a transparent support, it is cured by a polymerization reaction with ionizing radiation or heat to form an antiglare layer. It is also preferable to combine ionizing radiation curing and heat curing. Commercially available compounds can be used as the photo and thermal polymerization initiators, and they are described in “Latest UV Curing Technology” (p. 159, publisher: Kazuhiro Takahisa, publisher; Technical Information Association, 1991). Issued) and Ciba Specialty Chemicals catalog.

  30-99.9 mass% is preferable, as for the quantity of the binder in an anti-glare layer, 50-99.9 mass% is more preferable, and 80-99.5 mass% is especially preferable.

As described above, the antiglare layer of the present invention comprises a layer A comprising the coating composition (a) containing a binder and translucent fine particles, and a coating composition containing the binder but not containing translucent fine particles ( It can be formed by laminating an overcoat layer comprising b).
Hereinafter, the layer A and the overcoat layer will be described.

(Layer A)
In the present invention, the layer A contains at least a binder and translucent fine particles. The layer A is located on the support side of the overcoat layer, and the light-transmitting fine particles are substantially grounded to the support-side interface of the layer A (that is, the support-side interface of the antiglare layer). There is virtually nothing on board.
The average film thickness of the layer A is preferably 0.10 to 0.70 times the average particle diameter of the translucent fine particles, and is 0.15 to 0.55 times the average particle diameter of the translucent fine particles. It is more preferable that the average particle diameter of the translucent fine particles is 0.20 to 0.40 times.
The average film thickness of the layer A is preferably from 0.3 to 10.5 μm, more preferably from 0.4 to 8.3 μm, still more preferably from 0.6 to 6.0 μm. The average film thickness of the layer A can be calculated from an average value obtained by observing a cross section of the optical film of the present invention with an electron microscope and measuring 30 film thicknesses randomly.
In addition, when the interface of the layer A and an overcoat layer does not exist substantially, the said average film thickness shall point out the average coating film thickness of the coating composition for layer A formation. Here, the coating film thickness of a certain layer means the film thickness of the layer when the layer-forming coating composition is independently coated on a support and dried to form the layer. Similarly to the above, the average film thickness of the coating film can be calculated from an average value obtained by observing the cross section of the layer after formation with an electron microscope and measuring the film thickness at 30 random locations.

The coating amount of the coating composition (a) for layer A (hereinafter simply referred to as the coating liquid for layer A) is preferably 1 to 40 cc / m ² , and preferably ² to 30 cc in order to perform multilayer coating simultaneously with the overcoat layer. / ^{m 2,} more preferably, 3～20Cc / ^{m 2} is more preferable. When the coating amount is within this range, the liquid of the layer A and the overcoat layer is not excessively mixed when applied simultaneously with the overcoat layer, which is preferable.

The amount of translucent fine particles added to the coating solution of layer A is preferably 0.5 to 4.0% by mass, and preferably 0.5 to 3.0% by mass with respect to the total solid content of the coating solution. It is more preferable that it is 0.8-2.0 mass%. The amount of addition within this range is preferable because the convex portion of the surface unevenness of the antiglare layer is formed substantially by one translucent fine particle.
As the light-transmitting fine particles, those described as the light-transmitting fine particles of the above-described antiglare layer can be used.

The binder for the layer A is not particularly limited, and those described as the binder for the antiglare layer can be used.
The amount of the binder added to the coating solution of layer A is preferably 70 to 99.5% by mass, more preferably 80 to 99.5% by mass, based on the total solid content of the coating solution. More preferably, it is 90-99.2 mass%.

  The coating liquid for layer A is, for example, main matrix-forming binder monomers that are raw materials for polymers formed by curing with ionizing radiation or the like, translucent fine particles having a specific particle diameter, a polymerization initiator, It contains a polymer compound for adjusting viscosity, inorganic fine particle filler for curling reduction and refractive index adjustment, coating aid, leveling agent and the like.

(Polymer compound of layer A)
Layer A of the present invention may contain a polymer compound. By adding a polymer compound, curing shrinkage can be reduced and the viscosity of the coating solution can be adjusted.

  The polymer compound has already formed a polymer when added to the coating solution. Examples of the polymer compound include cellulose esters (eg, cellulose triacetate, cellulose diacetate, cellulose propionate, cellulose acetate propionate, cellulose acetate butyrate, and cellulose nitrate), urethane acrylates, and polyester acrylates. , (Meth) acrylic acid esters (for example, methyl methacrylate / (meth) methyl acrylate copolymer, methyl methacrylate / (meth) ethyl acrylate copolymer, methyl methacrylate / butyl (meth) acrylate) A resin such as a copolymer, a methyl methacrylate / styrene copolymer, a methyl methacrylate / (meth) acrylic acid copolymer, a polymethyl methacrylate, or the like) or polystyrene is preferably used.

The polymer compound is preferably contained in the range of 1 to 50% by mass, more preferably 5 to 40% by mass, based on the total binder of the layer A, from the viewpoint of the effect on curing shrinkage and the effect of increasing the viscosity of the coating solution. It is preferable to do.
The molecular weight of the polymer compound is preferably from 30,000 to 400,000 in terms of mass average, more preferably from 50,000 to 300,000, and even more preferably from 50,000 to 200,000.

(Inorganic filler of layer A)
In addition to the light-transmitting fine particles, the layer A of the present invention is inorganic depending on the purpose of adjusting the refractive index, adjusting the film strength, reducing the shrinkage of curing, and reducing the reflectance when a low refractive index layer is provided. It is also possible to use inorganic fillers for the fine particles. For example, it is composed of an oxide containing at least one metal element selected from titanium, zirconium, aluminum, indium, zinc, tin, and antimony, and the average particle diameter of primary particles is generally 0.2 μm or less, preferably It is also preferable to contain a fine high refractive index inorganic filler that is 0.1 μm or less, more preferably 0.06 μm or less and 1 nm or more.

  When it is necessary to lower the refractive index of the matrix in order to adjust the difference in refractive index from the translucent fine particles, a fine low refractive index inorganic filler such as silica fine particles or hollow silica fine particles is used as the inorganic filler. be able to. The preferred particle size is the same as that of the fine high refractive index inorganic filler.

  The surface of the inorganic filler is preferably subjected to a silane coupling treatment or a titanium coupling treatment, and a surface treatment agent having a functional group capable of reacting with a binder species on the filler surface is preferably used.

  The amount of the inorganic filler added to the coating solution of layer A is preferably 10 to 90% by mass, more preferably 20 to 80% by mass, and particularly preferably 30% with respect to the total solid content of the coating solution. -75 mass%.

  In addition, since the inorganic filler has a particle size sufficiently shorter than the wavelength of light, scattering does not occur, and the dispersion in which the filler is dispersed in the binder polymer has the property of an optically uniform substance.

(Leveling agent)
In particular, in order to ensure surface uniformity such as coating unevenness, drying unevenness, point defects, etc., it is preferable to contain either a fluorine-based surfactant or a silicone-based surfactant, or both in the coating solution of layer A. . In particular, a fluorine-based surfactant is preferably used because an effect of improving surface defects such as coating unevenness, drying unevenness, and point defects of the optical film of the present invention appears with a smaller addition amount. The purpose is to increase productivity by giving high-speed coating suitability while improving surface uniformity. Preferable examples of the fluorine-based surfactant include compounds described in paragraph numbers 0049 to 0074 of JP2007-188070A.

  The addition amount of the leveling agent (particularly fluoropolymer) used in the present invention to the coating liquid of the preferred layer A is in the range of 0.001 to 5% by mass, preferably 0.005 to the coating liquid. It is in the range of 3% by mass, more preferably in the range of 0.01-1% by mass. When the leveling agent is added in an amount of 0.001% by mass or more, the effect is sufficient, and when the leveling agent is 5% by mass or less, the coating film is sufficiently dried and good performance as a coating film (for example, reflectance) , Scratch resistance).

(Organic solvent for the coating solution of layer A)
An organic solvent can be added to the coating solution for layer A.

  As an organic solvent, for example, in an alcohol system, methanol, ethanol, n-propanol, isopropanol, n-butanol, isobutanol, sec-butanol, tert-butanol, isoamyl alcohol, 1-pentanol, n-hexanol, methyl amyl alcohol In the ketone system, methyl isobutyl ketone, methyl ethyl ketone, diethyl ketone, acetone, cyclohexanone, diacetone alcohol, etc., in the ester system, methyl acetate, ethyl acetate, n-propyl acetate, isopropyl acetate, isobutyl acetate, n-butyl acetate, Isoamyl acetate, n-amyl acetate, methyl propionate, ethyl propionate, methyl butyrate, ethyl butyrate, methyl acetate, methyl lactate, ethyl lactate, ether, acetal, 1,4 dioxane, te In hydrocarbons such as lahydrofuran, 2-methylfuran, tetrahydropyran, diethyl acetal, etc., hexane, heptane, octane, isooctane, ligroin, cyclohexane, methylcyclohexane, toluene, xylene, ethylbenzene, styrene, divinylbenzene, etc., halogen hydrocarbons In, carbon tetrachloride, chloroform, methylene chloride, ethylene chloride, 1,1,1-trichloroethane, 1,1,2-trichloroethane, trichloroethylene, tetrachloroethylene, 1,1,1,2-tetrachloroethane In the case of polyhydric alcohol and derivatives thereof, ethylene glycol, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monoacetate, diethylene glycol, propylene Glycolic acid, dipropylene glycol, butanediol, hexylene glycol, 1,5-pentanediol, glycerin monoacetate, glycerin ethers, 1,2,6-hexanetriol, etc. In fatty acid systems, formic acid, acetic acid, propionic acid, In the case of nitrogen compounds such as entrained acid, isoentangled acid, isovaleric acid, and lactic acid, formamide, N, N-dimethylformamide, acetamide, acetonitrile, and the like, and in the case of sulfur compounds, dimethyl sulfoxide and the like can be mentioned.

Among organic solvents, methyl isobutyl ketone, methyl ethyl ketone, cyclohexanone, acetone, toluene, xylene, ethyl acetate, 1-pentanol and the like are particularly preferable. In addition, an alcohol or a polyhydric alcohol solvent may be appropriately mixed with the organic solvent for the purpose of controlling cohesion.
These organic solvents may be used alone or in combination, and the total amount of the organic solvent in the coating solution of layer A is preferably 20% by mass to 90% by mass, and more preferably 30% by mass to 80% by mass. More preferably, it is most preferable to contain 40 mass%-70 mass%. In order to stabilize the surface shape of the layer A, it is preferable to use a solvent having a boiling point of less than 100 ° C. and a solvent having a boiling point of 100 ° C. or more.

(Viscosity of layer A)
In order to simultaneously coat the layer A and the overcoat layer, the viscosity of the coating solution for the layer A is preferably 10 mPa · S or more, more preferably 30 mPa · S or more, and further preferably 100 mPa · S or more and 1000 mPa · S or less. The method for adjusting the viscosity of the coating solution for layer A is not limited, but thickeners and thixotropic agents described in JP-A-2007-233185 can be used.

(Overcoat layer)
In the present invention, the overcoat layer is located on the layer A, and an antiglare layer having an average film thickness larger than the average particle diameter of the translucent fine particles is formed together with the layer A.
The average film thickness of the overcoat layer is preferably 0.50 to 1.90 times, more preferably 0.80 to 1.50 times the average particle diameter of the translucent fine particles, and the translucent property. More preferably, it is 0.90 to 1.40 times the average particle diameter of the fine particles.
The average film thickness of the overcoat layer is preferably 1.5 to 30.0 μm, more preferably 2.4 to 22.5 μm, still more preferably 2.7 to 21.0 μm. The average film thickness of the overcoat layer can be calculated from an average value obtained by observing the cross section of the optical film with an electron microscope and measuring 30 film thicknesses randomly.
When the average film thickness is in the above range, black reproducibility and antiglare properties can both be achieved, which is preferable.
In addition, when the interface of the layer A and an overcoat layer does not exist substantially, the said average film thickness shall point out the average coating film thickness of the coating composition for overcoat layer formation.

  It is preferable that the interface between the layer A and the overcoat layer is not substantially present. By substantially preventing the interface between the layer A and the overcoat layer from being present, curing shrinkage and rapid changes in hardness are suppressed, curling is reduced, and adhesion (peeling between the layer A and the overcoat layer) is improved. This is effective in suppressing interference unevenness.

The coating amount of the overcoat layer coating composition (b) (hereinafter simply referred to as the overcoat layer coating solution) is preferably 5 to 50 cc / m ² in order to be applied simultaneously with the layer A, and 6 to 40 cc. / ^{m 2,} more preferably, 10～30Cc / ^{m 2} is more preferable. A coating amount within this range is preferable because the liquid of the layer A and the overcoat layer is not excessively mixed when simultaneously applied with the overcoat layer.

  The coating liquid for the overcoat layer is, for example, a main monomer for matrix-forming binders, which is a raw material of a light-transmitting polymer formed by curing with ionizing radiation or the like, a polymerization initiator, preferably for adjusting the viscosity of the coating liquid. High molecular weight compounds, inorganic fine fillers for curling reduction and refractive index adjustment, coating aids, leveling agents, reactive silicone compounds, reactive fluorine compounds, and the like.

(Binder for overcoat layer)
The binder for forming the matrix of the overcoat layer is not particularly limited, but it is preferable to use those described as the binder for the antiglare layer.
The amount of the binder added to the overcoat layer coating solution is preferably 30 to 100% by mass, more preferably 50 to 100% by mass, and more preferably 80 to 100%, based on the total solid content of the coating solution. More preferably, it is mass%.

(High molecular compound of overcoat layer)
The overcoat layer of the present invention may contain a polymer compound. By adding a polymer compound, curing shrinkage can be reduced or the viscosity of the coating solution can be adjusted.
What was demonstrated as a high molecular compound of the above-mentioned layer A can be used for a high molecular compound, and a preferable compound and the usage-amount are also the same.

(Inorganic filler for overcoat layer)
In the overcoat layer of the present invention, inorganic fine particles are used as the inorganic filler depending on the purpose of adjusting the refractive index, adjusting the film strength, reducing curing shrinkage, and further reducing the reflectance when a low refractive index layer is provided. You can also. As the inorganic fine particles, those described as the inorganic filler of the layer A described above can be used, and preferable examples and use amounts thereof are also the same. However, from the viewpoint of reducing the reflectance, the inorganic fine particles are preferably included only in the overcoat layer in the antiglare layer.
Further, as the inorganic fine particles to be contained in the overcoat layer, silica having an average particle diameter of 1 nm or more and 1 μm or less is preferable, and particles having pores on at least one of the surface and the inside are preferable. As the hollow particles, hollow silica particles are preferable, and specific examples thereof are described in silica-based particles described in JP-A No. 2002-79616. The particle refractive index is preferably 1.15 to 1.40, more preferably 1.20 to 1.30.

(Leveling agent)
In particular, in order to ensure surface uniformity such as coating unevenness, drying unevenness, and point defects, it is preferable to contain either a fluorine-based surfactant or a silicone-based surfactant, or both in the coating composition. As a leveling agent, what was demonstrated as the leveling agent of the above-mentioned layer A can be used, and a preferable compound and the usage-amount are also the same.

(Reactive silicone or reactive fluorine compound)
For the purpose of imparting antifouling properties, water resistance, chemical resistance, slipping properties, etc., the overcoat layer of the present invention is appropriately added with known reactive silicones or fluorine compounds (antifouling agents, slipping agents), etc. Can be added. These reactive silicones or fluorine compounds should be included only in the overcoat layer in the antiglare layer from the viewpoint of changing the surface physical properties of the optical film and improving antifouling properties, water resistance, chemical resistance, slipperiness, etc. Is preferred. Further, it is preferable to use a reactive material, even if saponification described later is performed, the characteristics such as antifouling property, water resistance, chemical resistance, and slipping property are not lost.
When these additives are added, it is preferably added in the range of 0.01 to 20% by mass, more preferably 0.05 to the total solid content in the overcoat layer coating solution. It is a case where it is added in the range of 0% by mass, and particularly preferably 0.1 to 5% by mass.

(Reactive silicone compound)
As the reactive silicone compound, a compound having a polysiloxane structure can be used for the purpose of improving scratch resistance by imparting slipperiness and imparting antifouling property. There is no restriction | limiting in particular in the structure of a compound, The thing which has a substituent in the terminal and / or side chain of a compound chain | strand which contains multiple dimethylsilyloxy units as a repeating unit is preferable. The compound chain containing dimethylsilyloxy as a repeating unit may contain a structural unit other than dimethylsilyloxy. Hereinafter, it is referred to as a silicone compound.

The substituents may be the same or different, and a plurality of substituents are preferable. Examples of preferred substituents include groups including acryloyl group, methacryloyl group, vinyl group, aryl group, cinnamoyl group, oxetanyl group, fluoroalkyl group, polyoxyalkylene group, carboxyl group, amino group, epoxy group and the like.
From the viewpoint of improving the fixing property and antifouling property of the silicone compound in the film, a compound containing two or more (meth) acryloyl groups or epoxy groups in the molecule is preferred, and more preferably containing four or more. A compound.
Although there is no restriction | limiting in particular in molecular weight, It is preferable that it is 100,000 or less, It is more preferable that it is 50,000 or less, It is especially preferable that it is 3000-30000, It is most preferable that it is 5000-20000. Although there is no restriction | limiting in particular in silicone atom content of a silicone type compound, it is preferable that it is 18.0 mass% or more, it is especially preferable that it is 25.0-37.0 mass%, and 30.0-37.0. Most preferably, it is mass%.

Examples of preferable silicone compounds include Shin-Etsu Chemical Co., Ltd., X-22-160AS, X-22-162C, X-22-163C, X-22-164B, X22-164C, X-22-170DX, X-22-173DX, X-22-174DX, X-22-176D, X-22-176DX, X-22-176F, X-22-1821, X-22-2426, KF-105, KF-6001, KF-6002, KF-6003, (trade name) manufactured by Chisso Corporation, FM-0411, FM-0421, FM-0425, FM-0725, FM-1121, FM-4411, FM-4421, FM- 4425, FM-5511, FM-5521, FM-5525, FM-6611, FM-6621, FM-6625, FM-7725, FM- A11, FM-DA21, FM-DA25 (named above) or Gelest, CMS-626, CMS-222, DMS-U22, RMS-033, RMS-083, UMS-182, DMS-H21, DMS-H31, Examples thereof include, but are not limited to, HMS-301, FMS121, FMS123, FMS131, FMS141, and FMS221 (hereinafter, trade names).
When these additives are added, it is preferably added in the range of 0.01 to 20% by mass, more preferably 0.05 to 10%, based on the total solid content in the overcoat layer coating solution. It is a case where it is added in the range of mass%, particularly preferably 0.1 to 5 mass%.

(Reactive fluorine compounds)
As the reactive fluorine compound (hereinafter simply referred to as a fluorine compound), a fluorine compound used as an antifouling agent is preferable, and a compound having a fluoroalkyl group is more preferable. The fluoroalkyl group preferably has 1 to 20 carbon atoms, more preferably 1 to 10 carbon atoms, and a straight chain (for example, —CF ₂ CF ₃ , —CH ₂ (CF ₂ ) ₄ H, —CH ₂ (CF ₂ ) ₈ CF ₃ , —CH ₂ CH ₂ (CF ₂ ) ₄ H, etc.), but branched structures (eg, —CH (CF ₃ ) ₂ , —CH ₂ CF (CF ₃ ) ₂ , —CH (CH ₃ ) CF ₂ CF ₃ , —CH (CH ₃ ) (CF ₂ ) ₅ CF ₂ H, etc.), even an alicyclic structure (preferably a 5-membered ring or a 6-membered ring such as a perfluorocyclohexyl group) , A perfluorocyclopentyl group or an alkyl group substituted with these, and may have an ether bond (for example, —CH ₂ OCH ₂ CF ₂ CF ₃ , —CH ₂ CH ₂ OCH ₂ C). ₄ F ₈ H, -CH _{CH 2 OCH 2 CH 2 C 8} F 17, -CH 2 CH 2 OCF 2 CF 2 OCF 2 CF 2 H , etc.). A plurality of the fluoroalkyl groups may be contained in the same molecule.

The fluorine-based compound preferably further has a substituent that contributes to bond formation or compatibility with the overcoat layer film. The substituents may be the same or different, and a plurality of substituents are preferable. Examples of preferred substituents include acryloyl group, methacryloyl group, vinyl group, aryl group, cinnamoyl group, epoxy group, oxetanyl group, hydroxyl group, polyoxyalkylene group, carboxyl group, amino group and the like.
The fluorine-based compound may be a polymer or an oligomer, and may be a polymer or an oligomer composed of a monomer containing no fluorine atom and a monomer containing a fluorine atom, and the molecular weight is not particularly limited. Although there is no restriction | limiting in particular in fluorine atom content of a fluorine-type compound, It is preferable that it is 20 mass% or more, It is especially preferable that it is 30-70 mass%, It is most preferable that it is 40-70 mass%. Examples of preferred fluorine-based compounds include Daikin Chemical Industries, Ltd., R-2020, M-2020, R-3833, M-3833 (named above), Dainippon Ink, Megafac F-171. , F-172, F-179A, and defender MCF-300 (trade name), but are not limited thereto.

  From the viewpoint of improving the antifouling property of the overcoat layer and improving the scratch resistance of the coating film, a fluorine-based compound having a (meth) acrylate group is particularly preferable. Hereinafter, a preferable structure will be described.

[Telomer-type acrylate containing fluorine atoms]
As the fluorine-based compound having a (meth) acrylate group, a telomer acrylate containing a fluorine atom, for example, a fluorine-containing (meth) acrylic acid ester having a polymerization degree n represented by the following general formula (T-1) of k or more (Hereinafter also referred to as “telomer acrylate containing fluorine atoms” or simply “telomer”). This mixture has a degree of polymerization n of k, k + 1, k + 2,. . . Is a mixture of telomers. However, this mixture may inevitably contain telomers where n is smaller than k depending on the conditions of telomerization and the separation conditions of the reaction mixture.

As specific examples, _{n in} the group Rf (CF ₂ CF ₂ ) _n R ² CH ₂ CH ₂ O— in the following general formula (T-1) is k, k + 1, k + 2,. . . Is a mixture containing a plurality of fluorine-containing (meth) acrylic acid esters.

Formula (T-1): Rf ( CF 2 CF 2) nCH 2 CH 2 R 2 OCOCR 1 = CH 2
(In the formula, Rf represents any of a fluoroalkyl group having 1 to 10 carbon atoms, R ¹ represents a hydrogen atom or a methyl group, R ² represents a single bond or an alkylene group, and n represents a degree of polymerization. The degree of polymerization n is k or more (k is any integer of 3 or more).)

Examples of the telomer acrylate containing a fluorine atom in the general formula (T-1) include a (meth) acrylic acid moiety or a fully fluorinated alkyl ester derivative.
Specific examples of the telomer acrylate containing a fluorine atom that can be used in the present invention are shown below, but the present invention is not limited thereto.

[Acrylate having a C10 fluoroalkyl group]
As the fluorine-based compound, a compound represented by the following general formula (T-2) is also preferable.
General formula (T-2)

(In the formula, X and Y are either a (meth) acryloyloxy group or a hydroxyl group, and at least one is a (meth) acryloyloxy group.)

The fluorine-containing (meth) acrylic acid ester represented by the general formula (T-2) has a fluoroalkyl group having 10 carbon atoms having a trifluoromethyl group (CF _3- ) at its terminal. Even if a small amount of fluorine (meth) acrylate is used, the trifluoromethyl group is effectively oriented on the surface of the overcoat layer. If the fluoroalkyl has a small number of carbon atoms, the orientation on the surface of the overcoat layer tends to decrease. The fluorine-containing (meth) acrylic acid ester having a fluoroalkyl group having 11 or more carbon atoms is difficult to produce and obtain.

  Specific examples of the fluorine-containing (meth) acrylic acid ester represented by the general formula (T-2) include 1- (meth) acryloyloxy-2-hydroxy-4,4,5,5,6,6,7. , 7,8,8,9,9,10,10,11,11,12,12,13,13,13-heneicosafluorotridecane, 2- (meth) acryloyloxy-1-hydroxy-4 4,5,5,6,6,7,7,8,8,9,9,10,10,11,11,12,12,13,13,13-heneicosafluorotridecane and 1,2 -Bis (meth) acryloyloxy 4,4,5,5,6,6,7,7,8,8,9,9,10,10,11,11,12,12,13,13,13-hen Examples include eicosafluorotridecane.

[Acrylate having perfluoropolyether group]
In the present invention, perfluoropolyether group-containing acrylate compounds may be mentioned as fluorine compounds particularly useful for improving the slipperiness of the surface in addition to antifouling properties. Of these, heptafluoropropylene oxide group-containing acrylate is preferable. Although the example of a compound is given to the following, this invention is not limited to these.

(FC-1): HFPO-C (O) N (H) CH ₂ CH ₂ 0C (O) CH = CH ₂
(FC-2): HFPO-C (O) N (H) CH ₂ CH ₂ 0CH ₂ CH ₂ 0C (O) CH = CH ₂
(FC-3): HFPO-C (O) N (H) CH ₂ CH ₂ CH ₂ N (H) CH ₃ and equimolar Michael adduct of TMPTA
(FC-4): HFPO-C (O) N (H) C (CH ₂ 0C (O) CH = CH ₂ ) ₂ CH ₂ CH ₃
(FC-5): HFPO-C (O) N (H) C (CH ₂ 0C (O) CH = CH ₂ ) ₂ H
Here, HFPO- represents F (CF (CF ₃ ) CF ₂ 0) aCF (CF ₃ )-, and the average value of a is 6 to 7 (for example, 6.3). TMPTA represents trimethylolpropane triacrylate.

  A method for synthesizing these compounds is described in International Patent Publication WO2005 / 113690. When adding these additives, it is preferable to add in the range of 0.01-20 mass% of the total solid of a coating liquid in an overcoat layer coating liquid, More preferably, it is 0.05-15. It is a case where it is added in the range of mass%, particularly preferably 0.1 to 10 mass%.

(Organic solvent for overcoat coating solution)
An organic solvent can be added to the coating liquid for the overcoat layer.
Examples of the organic solvent include the same organic solvents as those in the layer A described above.
The organic solvent may be used alone or in combination, and it is preferably contained in the coating solution for the overcoat layer in an amount of 220% by mass to 90% by mass as the total amount of the organic solvent, and 30% by mass to 80% by mass. Is more preferable, and it is most preferable to contain 40 mass%-70 mass%. In order to stabilize the surface shape of the layer A, it is preferable to use a solvent having a boiling point of less than 100 ° C. and a solvent having a boiling point of 100 ° C. or more.
Any organic solvent can be selected as the organic solvent in each of the coating liquids of the layer A and the overcoat layer, but there is a combination of organic solvents in which the solvents used for the layer A and the overcoat layer are mutually soluble. preferable. More preferably, a part of the organic solvent used for the layer A and the overcoat layer is the same organic solvent. When the solvents used for the layer A and the overcoat layer are dissolved in each other, when they are simultaneously layered, no precipitates are formed at the interface between the layer A and the overcoat layer, so that the adhesion is excellent, and Interference unevenness can be reduced by substantially eliminating the interface between the layer A and the overcoat layer.

(Refractive index of antiglare layer / overcoat layer)
In the optical film of the present invention, the surface refractive index of the antiglare layer is preferably from 1.25 to 1.49, more preferably from 1.25 to 1.49. Here, the “surface refractive index” is an average refractive index at a depth from the outermost surface of the antiglare layer (that is, the outermost surface of the overcoat layer) to 100 nm. When the surface refractive index is in the above range, the reflectance is reduced and black reproducibility is improved, which is preferable.
The refractive index of the overcoat layer (average refractive index of the entire overcoat layer) is not particularly limited, but is preferably from 1.25 to 2.00, more preferably from 1.25 to 1.49. When the optical film of the present invention is used as the outermost surface of the display material and the overcoat layer is the uppermost layer of the film, the refractive index of the overcoat layer is preferably from 1.25 to 1.49, more preferably 1 30 to 1.47. In particular, in order to make the fingerprint adhering mark inconspicuous, by setting it to 1.45 or more and 1.48 or less, it is effective because the fat and oil of the fingerprint becomes close to the refractive index. Moreover, since the anti-glare property is imparted to the optical film, the fingerprint mark is further less visible and is particularly effective.

  On the other hand, when a low refractive index layer is further provided as an optical interference layer on the overcoat layer, the refractive index of the overcoat layer is preferably 1.46 or more and 2.00 or less, and 1.49 or more and 2.00 or less. More preferred is 1.58 or more and 1.70 or less. In order to increase the refractive index, it is preferable to use an inorganic fine particle having a high refractive index for the overcoat layer.

(Surface free energy of antiglare layer / overcoat layer)
In the optical film of the present invention, the surface free energy of the antiglare layer (that is, the surface free energy of the overcoat layer) is preferably 30 mN / m or less, and more preferably 20 mN / m or less. When the surface free energy is within the above range, it is preferable because fingerprints and magic ink are less likely to adhere and the antifouling property is improved. The surface free energy (γsv: unit, mN / m) of the film of the present invention is D.E. K. Owens: J.M. Appl. Polym. Sci. , 13, 1741 (1969), and can be determined from the contact angles of pure water and methylene iodide CH ₂ I ₂ experimentally determined on the film.

(Viscosity of overcoat layer)
In order to simultaneously apply the layer A and the overcoat layer, the viscosity of the overcoat layer is preferably 30 mPa · S or less, more preferably 10 mPa · S or less, and further preferably 0.4 mPa · S or more and 5 mPa · S or less. The method for adjusting the viscosity of the overcoat layer coating solution is not limited, but thickeners and thixotropic agents described in JP-A-2007-233185 can be used.

(Interface between layer A and overcoat layer)
In the present invention, the interface between the layer A and the overcoat layer may be clear. A configuration that does not exist is also preferable.

As a preferable first embodiment in which the interface between the layer A and the overcoat layer does not substantially exist, there is an embodiment in which there is a region (composition change layer) in which the composition gradually changes in the vicinity of the interface between both layers. In the present invention, the composition refers to the constituent ratio of the binder and / or translucent fine particles in the cured film.
In this embodiment, the thickness of the composition change layer is preferably 0.05 to 5 μm, more preferably 0.1 to 2 μm. When the refractive index of the overcoat layer component alone is different from the refractive index of the layer A component alone by 0.02 or more, the thickness of the composition change layer is particularly preferably 0.05 to 1 μm. The composition change layer is a layer whose composition gradually changes from the composition of the bulk overcoat layer to the composition of the bulk layer A between the upper end and the lower end.

  As a preferred second embodiment in which the interface between the layer A and the overcoat layer does not substantially exist, the layer A and the overcoat layer further form another interface mixed layer at the interface. In this embodiment, the thickness of the interfacial mixed layer is preferably 0.05 to 1 μm, more preferably 0.05 to 0.5 μm.

  As a preferred third embodiment in which the interface between the layer A and the overcoat layer does not substantially exist, the components of the layer A and the overcoat layer form a sea-island structure or a co-continuous phase that is phase-separated at the interface. Is. In this embodiment, the equivalent sphere diameter of the phase-separated island structure portion is preferably 0.01 to μm, more preferably 0.02 to 0.3 μm, and most preferably 0.02 to 0.15 μm. Of these embodiments in which the interface is not substantially present, the first embodiment is particularly preferable.

  These interfacial states are formed by simultaneously applying layers A and an overcoat layer, and using a component that easily penetrates the layer A as an overcoat layer or a component that is easily extracted into the overcoat layer as a layer A. It is possible to control by including it.

  Moreover, in order to improve the adhesiveness between interfaces, the hydrolyzate and partial condensate of the organosilane compound of Unexamined-Japanese-Patent No. 2007-233185 may be contained in both or one of the layer A and an overcoat layer. preferable. The content of the hydrolyzate and partial condensate of the organosilane compound is preferably small in the case of the layer A that is a relatively thin film and large in the case of the overcoat layer that is a thick film. The content is preferably 0.1 to 50% by mass, and preferably 0.5 to 30% by mass based on the total solid content of the containing layer (added layer), considering the effect, refractive index, film shape / surface shape, and the like. More preferred is 1 to 15% by mass.

(Formation of antiglare layer)
In the present invention, the antiglare layer comprises a coating composition (a) (a coating liquid for layer A) containing a binder and translucent fine particles, and a coating composition (b) containing the binder but not containing translucent fine particles. ) (Coating solution for overcoat layer) and a multilayer coating on the support at the same time. Here, from the viewpoint of grounding the translucent fine particles to the support side interface, it is preferable to apply the coating composition (a) to the side closer to the support.
FIG. 4 is a cross-sectional view of a coater that can be used to practice the present invention. The coater 10 shown in FIG. 4 applies the lowermost coating solution 14 from the slot die 13 to the bead 14a on the transparent support web W supported by the backup roll 11 and continuously running. A slide type coating head is provided in the vicinity of the tip of the slot die 13, and the intermediate layer coating solution flows on the slide 51 and the uppermost layer coating solution flows on the slide 53. At the same time, three layers are applied to form a coating film 14b. By using only the slot die 13 and the slide 51 without flowing the coating solution on the slide 53, two layers can be applied simultaneously. For example, by applying the coating composition (a) from the slot die 13 and coating the coating composition (b) from the slide 51, the layer A and the overcoat layer can be formed by simultaneous multilayer coating.

  Inside the slot die 13, a pocket 15, a slot 16, and pockets 50 and 52 are formed. The pockets 15, 50, 52 have a cross section formed by a curved line and a straight line, and may be substantially circular or semicircular, for example. The pockets 15, 50, 52 are coating liquid reservoir spaces extended with the cross-sectional shape in the width direction of the slot die 13, and the effective extension length is generally equal to or slightly longer than the coating width. Is. The coating liquid is supplied to the pockets 15, 50, 52 from the side surface of the slot die 13 or from the center of the surface opposite to the slot opening 16a. The pockets 15, 50, 52 are provided with stoppers that prevent the coating liquid from leaking out.

  The slot 16 is a flow path of the coating liquid 14 from the pocket 15 to the web W, and has a cross-sectional shape in the width direction of the slot die 13 similarly to the pocket 15, and the opening 16a located on the web side is generally Using a width regulating plate (not shown), the width is adjusted to be approximately the same as the coating width. The angle between the slot tip of the slot 16 and the tangent in the web running direction of the backup roll 11 is preferably 30 ° or more and 90 ° or less.

  The tip lip 17 of the slot die 13 where the opening 16a of the slot 16 is located is tapered, and the tip is a flat part 18 called a land. In this land 18, the upstream side in the running direction of the web W with respect to the slot 16 is referred to as an upstream lip land 18 a and the downstream side is referred to as a downstream lip land 18 b.

  The slides 51 and 53 are on the upper surface of the slot die 13, and the coating liquid flows from the pockets 50 and 52, respectively, and is adjusted so that the width is approximately the same as the coating width.

  The length of the slide surface is preferably in the range of 1.5 mm to 50 mm, more preferably 1.5 mm to 20 mm, and most preferably 2 mm to 10 mm. It is desirable to adjust the length of the slide surface according to the viscosity of the coating solution and the volatility of the solvent used.

The coating amount to flow from the slide type coating head is preferably 100 cc / ^{m 2} or less, more preferably 1~80cc / ^{m 2,} more preferably from 2~50cc / ^{m 2.}
Especially if the coating amount than 4 cc / m ² is small, since the slide surface scissile the liquid, then was runaway at 5 cc / m ² or more flow, better adjusted to a predetermined amount.

In order to prevent volatilization of the coating liquid on the slide surface, it is desirable to attach a cover that covers the entire slide surface. Cover 55 and sliding surfaces 51 and 53, the cross-sectional area is 550 mm ² or less is desirable to surround the backup roll W, more preferably 250 mm ² or less, and most preferably 60 mm ² or less.
Note that slide-type coating heads are known and disclosed in, for example, Japanese Patent Application Laid-Open No. 2003-164788.

(Layer A / Cure of overcoat layer)
The layer A and the overcoat layer are simultaneously applied as a multilayer on the support and then cured. Curing can be performed by carrying out light irradiation, electron beam irradiation, heat treatment or the like, and crosslinking or polymerizing the binder component in each coating solution.
In the case of ultraviolet irradiation, ultraviolet rays emitted from light such as an ultrahigh pressure mercury lamp, a high pressure mercury lamp, a low pressure mercury lamp, a carbon arc, a xenon arc, a metal halide lamp, etc. can be used. Curing with ultraviolet rays is preferably performed under an atmosphere of oxygen concentration of 4% by volume or less, more preferably 2% by volume or less, and most preferably 0.5% by volume or less by nitrogen purge or the like.

(Physical properties of optical film)
In the optical film of the present invention, the haze value resulting from surface scattering is preferably 0 to 10%, more preferably 0 to 7%, and further preferably 0.5 to 5%. The internal haze value is preferably 0 to 25%, more preferably 0 to 10%, still more preferably 0 to 1%. When the haze due to surface scattering and the internal haze are in this range, in addition to achieving both antiglare properties and black reproducibility, a high contrast can be obtained when an LCD panel is used.
The haze value resulting from surface scattering can be measured by the following [1] to [3].
[1] The total haze value (H) of the obtained film is measured according to JIS-K7136.
[2] Add a few drops of linseed oil to the front and back of the obtained film, and use two 1 mm thick glass plates (micro slide glass product number S9111, made by MATSUNAMI) from the front and back to make two completely The value obtained by subtracting the haze measured by sandwiching only silicone oil between two separately measured glass plates was measured with the surface of the glass plate closely adhered and the surface haze removed. The internal haze (Hi) was calculated.
[3] A value obtained by subtracting the internal haze (Hi) calculated in [2] from the total haze (H) measured in [1] above was calculated as the surface haze (Hs) of the film.

  In the optical film of the present invention, the arithmetic average roughness Ra is preferably from 0.05 to 0.25 μm, more preferably from 0.07 to 0.20 μm, most preferably according to JIS-B0601 (1994). Is 0.08 or more and 0.18 μm or less. The average interval Sm between the irregularities is preferably 0.03 or more and 0.5 mm or less, more preferably 0.04 or more and 0.3 mm or less, and most preferably 0.06 or more and 0.2 mm or less. The 10-point average roughness Rz is preferably 0.2 to 2.0 μm, more preferably 0.25 to 1.6 μm, and most preferably 0.3 to 1.3 μm.

In the optical film of the present invention, the inclination angle θ of the irregularities on the surface of the antiglare layer is a ratio θ (1) occupied by a region of 0 ° ≦ θ ≦ 1 ° [area occupied by a region of 0 ° ≦ θ ≦ 1 ° with respect to a constant area. %] Is preferably 60% or more and 99% or less, more preferably 70% or more and 94% or less, and particularly preferably 85% or more and 93% or less. θ (1) is a scale representing the ratio of a region having no uneven peak of the anti-glare layer, that is, a flat region because the inclination angle θ of the surface unevenness of the anti-glare layer is 0 ° ≦ θ ≦ 1 °. is there.
If θ (1) is in the above range, good antiglare property can be obtained, glare caused by reflection of a fluorescent lamp or the like on the display surface can be suppressed, and point defects due to coarse particles can be reduced. Can do. Furthermore, when the optical film of the present invention is arranged on the outermost surface of the display and the display is displayed in black, no white-brown color occurs and good black reproducibility can be obtained.

The distribution of the inclination angle θ is determined by the following method.
In other words, assuming that the apex of a triangle having an area of 0.5 to 2 square micrometers is the film substrate surface (support surface), three perpendicular lines extending vertically upward from that point are formed by three points intersecting the film surface. The angle θ formed between the normal of the triangular surface and the perpendicular extending vertically upward from the support is the surface inclination angle, and an area of 250,000 square micrometers (0.25 square millimeters) or more on the substrate The inclination angle distribution at all measurement points when measuring by dividing into triangles is examined.

A method for measuring the tilt angle will be described in detail with reference to FIGS.
First, the film is divided into meshes having an area on the support surface of 0.5 to 2 square micrometers (see FIG. 5). FIG. 6 is a diagram in which three points of the divided mesh are extracted. A perpendicular line is extended vertically upward from three points on the support, and points where the three points intersect the surface are designated as A, B, and C. An inclination angle is defined as an angle θ formed by a normal line DD ′ of the triangle ABC plane and a perpendicular line OO ′ extending vertically upward from the support. FIG. 7 is a cross-sectional view of the film taken along the plane P including the point O′DD ′. A line segment EF is an intersection line between the triangle ABC and the plane P. The measurement area is preferably 250,000 square micrometers (0.25 square millimeters) or more on the support, and this surface is divided into triangles on the support and measured to determine the inclination angle. There are several devices to measure, but an example will be described. A case will be described in which an SXM520-AS150 model manufactured by Micromap (USA) is used as the apparatus. For example, when the objective lens is 10 times, the measurement unit of the tilt angle is 0.8 square micrometers, and the measurement range is 500,000 square micrometers (0.5 square millimeters). If the magnification of the objective lens is increased, the measurement unit and the measurement range are reduced accordingly. The measurement data can be analyzed using software such as MAT-LAB, and the tilt angle distribution can be calculated.

  In the optical film of the present invention, when the surface roughness and the inclination angle frequency of the irregularities on the surface of the antiglare layer are in the above range, it is difficult to visually recognize point defects, and when the antireflection layer is coated, the reflectance is low, black An optical film having excellent reproducibility can be obtained.

  Hereinafter, layers other than the antiglare layer (layer A / overcoat layer) of the optical film of the present invention will be described.

(Low refractive index layer)
The optical film of the present invention preferably has a low refractive index layer having a lower refractive index than the overcoat layer in order to reduce the reflectance. The refractive index of the low refractive index layer is preferably 1.20 to 1.46, more preferably 1.25 to 1.46, and particularly preferably 1.30 to 1.40. The thickness of the low refractive index layer is preferably 50 to 200 nm, and more preferably 70 to 100 nm. The haze of the low refractive index layer is preferably 3% or less, more preferably 2% or less, and most preferably 1% or less.

As a preferable curable composition for forming the low refractive index layer,
(1) A composition containing a fluorine-containing compound having a crosslinkable or polymerizable functional group,
(2) a composition comprising as a main component a hydrolysis-condensation product of a fluorine-containing organosilane material;
(3) a composition containing a monomer having two or more ethylenically unsaturated groups and inorganic fine particles having a hollow structure;
Is mentioned.

(1) Fluorine-containing compound having a crosslinkable or polymerizable functional group As the fluorine-containing compound having a crosslinkable or polymerizable functional group, co-polymerization of a fluorine-containing monomer and a monomer having a crosslinkable or polymerizable functional group Coalescence can be mentioned. Specific examples of these fluorine-containing polymers are described in JP2003-222702A, JP2003-183322A, and the like.

  As described in JP 2000-17028 A, a curing agent having a polymerizable unsaturated group may be used in combination with the above polymer. Moreover, combined use with the compound which has a fluorine-containing polyfunctional polymerizable unsaturated group as described in Unexamined-Japanese-Patent No. 2002-145952 is also preferable. Examples of the compound having a polyfunctional polymerizable unsaturated group include the above-described monomers having two or more ethylenically unsaturated groups. Moreover, the hydrolysis-condensation product of the organolane described in Unexamined-Japanese-Patent No. 2004-170901 is also preferable, and the hydrolysis-condensation product of the organosilane containing a (meth) acryloyl group is especially preferable. These compounds are particularly preferred because they have a large combined effect for improving scratch resistance, particularly when a compound having a polymerizable unsaturated group is used in the polymer body.

  When the polymer itself does not have sufficient curability, necessary curability can be imparted by blending a crosslinkable compound. For example, when the polymer body contains a hydroxyl group, various amino compounds are preferably used as the curing agent. The amino compound used as the crosslinkable compound is, for example, a compound containing one or both of a hydroxyalkylamino group and an alkoxyalkylamino group in total, specifically, for example, a melamine compound, Examples include urea compounds, benzoguanamine compounds, glycoluril compounds, and the like. For curing these compounds, an organic acid or a salt thereof is preferably used.

(2) Composition mainly composed of hydrolyzed condensate of fluorine-containing organosilane material The composition mainly composed of hydrolyzed condensate of fluorine-containing organosilane compound also has a low refractive index and the hardness of the coating surface. Is preferable. A condensate of a tetraalkoxysilane with a hydrolyzable silanol-containing compound at one or both ends with respect to the fluorinated alkyl group is preferred. The specific composition is described in Unexamined-Japanese-Patent No. 2002-265866, 317152.

(3) A composition containing a monomer having two or more ethylenically unsaturated groups and inorganic fine particles having a hollow structure As yet another preferred embodiment, a low refractive index layer comprising low refractive index particles and a binder can be mentioned. . The low refractive index particles may be organic or inorganic, but particles having pores inside are preferable. As the hollow particles, hollow silica particles are preferable, and specific examples thereof are described in silica-based particles described in JP-A No. 2002-79616. The particle refractive index is preferably 1.15 to 1.40, more preferably 1.20 to 1.30. Examples of the binder include a monomer having two or more ethylenically unsaturated groups described on the page of the antiglare layer A, JP-A No. 2002-243907, JP-A No. 2002-372601, JP-A No. 2003-26732, Copolymers of perfluoroolefin and vinyl ethers or vinyl esters described in JP-A-2003-222702, JP-A-2003-294911, JP-A-2003-329804, JP-A-2004-4444, and JP-A-2004-45462 Can be mentioned.

  It is preferable to add a polymerization initiator to the low refractive index layer of the present invention. When a radically polymerizable compound is contained, 1 to 10 parts by mass, preferably 1 to 5 parts by mass of a polymerization initiator can be used with respect to the compound. Commercially available compounds can be used as the photo and thermal polymerization initiators, and they are described in “Latest UV Curing Technology” (p. 159, publisher: Kazuhiro Takahisa, publisher; Technical Information Association, 1991). Issued) and Ciba Specialty Chemicals catalog.

  In the low refractive layer of the present invention, inorganic fine particles can be used in combination. In order to impart scratch resistance, fine particles having a particle size of 15% to 150%, preferably 30% to 100%, more preferably 45% to 60% of the thickness of the low refractive index layer can be used. .

In the low refractive index layer of the present invention, for the purpose of imparting properties such as antifouling property, water resistance, chemical resistance, and slipping property, a known polysiloxane-based or fluorine-based antifouling agent, slipping agent, etc. are appropriately used. Can be added.
In addition, for the purpose of imparting scratch resistance or scratch resistance after chemical treatment, the polymerization described in JP-A-10-25388, JP-A-2000-17028 and JP-A-2002-145952 It is preferable to use a compound having an unsaturated bond in combination.

  The low refractive index layer is formed by applying a coating solution for forming the low refractive index layer on the lower layer (such as an antiglare layer) and irradiating with light or heating (irradiating with ionizing radiation such as ultraviolet rays, preferably under heating. It is cured by irradiation with ionizing radiation, and a low refractive index layer is formed.

  FIG. 3 schematically shows an example of an academic film including a low refractive index layer. The optical film 300 shown in FIG. 3 has an antiglare layer 302 having translucent fine particles 303 on a support 301. The antiglare layer 302 includes a layer A and an overcoat layer B. The optical film 303 further has a low refractive index layer 304 on the antiglare layer 302. With this configuration, in addition to achieving both black reproducibility and antiglare properties, a film that is further excellent in antireflection properties can be obtained.

(High refractive index layer, medium refractive index layer)
The optical film of the present invention has a refractive index higher than that of the antiglare layer (overcoat layer) and the low refractive index layer between the antiglare layer and the low refractive index layer in order to enhance antireflection properties. It is preferable to further have a high, high refractive index layer.
It is also preferable to further include a middle refractive index layer having a refractive index higher than that of the antiglare layer and lower than that of the high refractive index layer between the antiglare layer and the high refractive index layer. .
Hereinafter, in the present specification, the high refractive index layer and the medium refractive index layer may be collectively referred to as a high refractive index layer. In the present invention, “high”, “medium”, and “low” in the high refractive index layer, medium refractive index layer, and low refractive index layer represent the relative refractive index relationship between the layers. In terms of the relationship with the support, the refractive index preferably satisfies the relationship of support> low refractive index layer, high refractive index layer> support.
In the present specification, the high refractive index layer, the middle refractive index layer, and the low refractive index layer may be collectively referred to as an antireflection layer.
Specific examples of the high refractive index layer and the medium refractive index layer include the high refractive index layer and the medium refractive index layer described in JP-A-2008-262187, and these aspects are also applicable to the present invention. Can do.

(Conductive particles)
In order to impart conductivity to the optical film of the present invention, various conductive particles can be used. In particular, from the viewpoint of preventing dust adhesion, the inorganic fine particles used for the overcoat layer are preferably conductive fine particles.
The conductive particles are preferably formed from a metal oxide or nitride. Examples of metal oxides or nitrides include tin oxide, indium oxide, zinc oxide and titanium nitride. Tin oxide and indium oxide are particularly preferred. The conductive inorganic particles are mainly composed of oxides or nitrides of these metals, and can further contain other elements. The main component means a component having the largest content (mass%) among the components constituting the particles. Examples of other elements include Ti, Zr, Sn, Sb, Cu, Fe, Mn, Pb, Cd, As, Cr, Hg, Zn, Al, Mg, Si, P, S, B, Nb, In, V and halogen atoms are included. In order to increase the conductivity of tin oxide and indium oxide, it is preferable to add Sb, P, B, Nb, In, V and a halogen atom. Particularly preferred are tin oxide (ATO) containing Sb and indium oxide (ITO) containing Sn. The ratio of Sb in ATO is preferably 3 to 20% by mass. The ratio of Sn in ITO is preferably 5 to 20% by mass.

The conductive inorganic particles may be surface treated. The surface treatment is performed using an inorganic compound or an organic compound. Examples of inorganic compounds used for the surface treatment include alumina and silica. Silica treatment is particularly preferred. Examples of the organic compound used for the surface treatment include polyols, alkanolamines, stearic acid, silane coupling agents, and titanate coupling agents. Silane coupling agents are most preferred. Two or more kinds of surface treatments may be performed in combination.
The shape of the conductive inorganic particles is preferably a rice grain shape, a spherical shape, a cubic shape, a spindle shape or an indefinite shape. Two or more kinds of conductive particles may be used in combination in a specific layer or as a film.
The conductive inorganic particles can be used for forming an antistatic layer in a dispersion state.

(Dispersant)
In order to ensure the dispersion stability of inorganic fine particles and conductive particles used in the present invention, film strength after curing, etc., it is described in JP-A-11-153703, US Pat. No. 6,210,858 and the like. Such a polyfunctional (meth) acrylate monomer and an anionic group-containing (meth) acrylate dispersant are preferably contained in the coating composition.

(Leveling agent)
It is preferable to use the aforementioned leveling agent in at least one of the high refractive index layer and the medium refractive index layer of the present invention. By using it for the high refractive index layer or the medium refractive index layer of the present invention, it is possible to improve the film thickness non-uniformity and the repellency of the coated material due to the surface irregularities of the antiglare layer. That is, in the present invention, the high refractive index layer preferably contains a leveling agent, and the medium refractive index layer preferably contains a leveling agent.

  In the present invention, the preferred integrated reflectance of the antireflection optical film provided with a low refractive index layer or the like is preferably 3.0% or less, more preferably 2.0% or less, and most preferably 1.5%. Below 0.2% or more. Since sufficient anti-glare property can be obtained even if light scattering on the surface of the optical film is reduced by lowering the integrated reflectance, an anti-glare anti-reflection film excellent in black reproducibility can be obtained.

(Support)
As the support for the optical film of the present invention, a plastic film is preferably used. Examples of the polymer forming the plastic film include cellulose acylate (eg, triacetyl cellulose, diacetyl cellulose, typically TAC-TD80U, TD80UF, etc., manufactured by Fuji Film), polyamide, polycarbonate, polyester (eg, polyethylene terephthalate, polyethylene). Naphthalate), polystyrene, polyolefin, norbornene resin (Arton: trade name, manufactured by JSR), amorphous polyolefin (ZEONEX: trade name, manufactured by ZEON CORPORATION), (meth) acrylic resin (ACRYPET VRL20A: product) Name, manufactured by Mitsubishi Rayon Co., Ltd. and ring structure-containing acrylic resins described in JP-A No. 2004-70296 and JP-A No. 2006-171464). Of these, triacetyl cellulose, polyethylene terephthalate, and polyethylene naphthalate are preferable, and triacetyl cellulose is particularly preferable.
The thickness of the support is preferably 15 to 100 μm, more preferably 15 to 80 μm, and still more preferably 15 to 60 μm, from the viewpoint of thinning the LCD panel.

  When the optical film of the present invention is used in a liquid crystal display device, it is disposed on the outermost surface of the display by providing an adhesive layer on one side. Moreover, you may combine the optical film and polarizing plate of this invention. When the transparent support is triacetyl cellulose, triacetyl cellulose is used as a protective film for protecting the polarizing film of the polarizing plate. Therefore, it is preferable in terms of cost to use the optical film of the present invention as it is for the protective film.

(Saponification treatment)
When the optical film of the present invention is disposed on the outermost surface of a display by providing an adhesive layer on one side or used as it is as a protective film for a polarizing plate, the optical film on the transparent support is sufficient for adhesion. It is preferable to carry out a saponification treatment after forming the outermost layer. The saponification treatment is performed by a known method, for example, by immersing the film in an alkali solution for an appropriate time. After being immersed in the alkaline solution, it is preferable to sufficiently wash with water or neutralize the alkaline component by dipping in a dilute acid so that the alkaline component does not remain in the film.
By saponification treatment, the surface of the transparent support opposite to the side having the outermost layer is hydrophilized.

(Application method)
Each layer of the optical film of the present invention can be formed by the following coating method, but is not limited to this method. Dip coating method, air knife coating method, curtain coating method, roller coating method, wire bar coating method, gravure coating method and extrusion coating method (die coating method) (see US Pat. No. 2,681,294), micro gravure coating method, etc. Known methods are used, and among them, the micro gravure coating method and the die coating method are preferable.

  In particular, when an overcoat layer is simultaneously coated on the layer A, a method of simultaneously coating two or more layers with a single coating apparatus (Japanese Patent Laid-Open Nos. 2002-86050, 2003-260400, and 7). -108213, Japanese Patent Application Laid-Open No. 2007-112426, and Japanese Patent Application Laid-Open No. 2007-164166) are preferable. A method of applying two or more layers in one winding by arranging coating / drying / curing devices in multiple stages (see Japanese Patent Application Laid-Open No. 2003-205264) has been disclosed. The interface between the overcoat layer and the overcoat layer becomes clear, causing problems of adhesion, uneven interference, and curling.

  Thereafter, the monomer contained in each functional layer is polymerized and cured by light irradiation or heating. Thereby, each layer is formed. If necessary, the functional layer can be a plurality of layers.

(Polarizer)
The polarizing plate is mainly composed of two protective films that protect both the front and back sides of the polarizing film. The optical film of the present invention is preferably used for at least one of the two protective films sandwiching the polarizing film from both sides. The manufacturing cost of a polarizing plate can be reduced because the optical film of the present invention also serves as a protective film. In addition, by using the optical film of the present invention as the outermost layer, reflection of external light and the like can be prevented, and a polarizing plate having excellent scratch resistance, antifouling property and the like can be obtained.

  The hydrophilized surface is particularly effective for improving the adhesion with a polarizing film containing polyvinyl alcohol as a main component. In addition, the hydrophilic surface makes it difficult for dust in the air to adhere to it, making it difficult for dust to enter between the polarizing film and the optical film when bonded to the polarizing film, and is effective in preventing point defects caused by dust. It is.

  The saponification treatment is preferably carried out so that the contact angle of water on the surface of the transparent support opposite to the side having the outermost layer is 40 ° or less. More preferably, it is 30 ° or less, particularly preferably 20 ° or less.

(Image display device)
The optical film of the present invention is applied to an image display device such as a liquid crystal display device (LCD), a plasma display panel (PDP), an electroluminescence display (ELD), a cathode ray tube display device (CRT), and a surface electric field display (SED). can do. It is particularly preferably used for a liquid crystal display (LCD). Since the optical film of the present invention has a transparent support, it is used by bonding the transparent support side to the image display surface of the image display device.

  When the optical film of the present invention is used as one side of a surface protective film of a polarizing film, it is twisted nematic (TN), super twisted nematic (STN), vertical alignment (VA), in-plane switching (IPS), optically. It can be preferably used for a transmissive, reflective, or semi-transmissive liquid crystal display device in a mode such as a compensated bend cell (OCB).

  In order to describe the present invention in detail, examples will be described below, but the present invention is not limited thereto. Unless otherwise specified, “part” and “%” are based on mass.

[Example 1]
(Preparation of sol solution a)
To a reactor equipped with a stirrer and a reflux condenser, 120 parts of methyl ethyl ketone, 100 parts of acryloyloxypropyltrimethoxysilane (KBM-5103, manufactured by Shin-Etsu Chemical Co., Ltd.), 3 parts of diisopropoxyaluminum ethyl acetoacetate are added and mixed. After that, 30 parts of ion exchanged water was added and reacted at 60 ° C. for 4 hours, and then cooled to room temperature to obtain a sol solution a. The mass average molecular weight was 1600, and among the components higher than the oligomer component, the component having a molecular weight of 1000 to 20000 was 100%. Further, from the gas chromatography analysis, the raw material acryloyloxypropyltrimethoxysilane did not remain at all.

(Preparation of coating liquid for forming layer A and coating liquid for forming overcoat layer)
The composition of the coating solution for forming layer A and the coating solution for forming overcoat layer used in this example is described below.

Composition of coating liquid 1 for forming layer A PET-30 30.0 parts by mass DPHA 18.0 parts by mass MX-600 (translucent fine particles) 0.20 parts by mass SSX106FB (translucent fine particles) 0.34 parts by mass Irgacure 127 1.5 parts by mass SP-13 0.14 parts by mass Polymethyl methacrylate (20%) 9.0 parts by mass Methyl isobutyl ketone 28.0 parts by mass Methyl ethyl ketone 13.0 parts by mass

Composition of coating liquid 2 for forming layer A PET-30 28.0 parts by mass DPHA 16.8 parts by mass SX-350HL (translucent fine particles) 0.25 parts by mass Irgacure 127 1.5 parts by mass SP-13 0.14 Parts by weight polymethyl methacrylate (20%) 4.0 parts by weight methyl isobutyl ketone 20.3 parts by weight methyl ethyl ketone 13.4 parts by weight

Composition of coating liquid 3 for forming layer A PET-30 45.9 parts by mass MX-1000 (translucent fine particles) 3.12 parts by mass Irgacure 127 1.5 parts by mass SP-13 0.1 parts by mass Polymethyl methacrylate ( 20%) 6.0 parts by weight Methyl isobutyl ketone 23.0 parts by weight Methyl ethyl ketone 13.4 parts by weight

Composition of coating liquid 4 for forming layer A PET-30 30.0 parts by mass DPHA 18.0 parts by mass MX-150H (translucent fine particles) 0.53 parts by mass Irgacure 127 1.5 parts by mass SP-13 0.14 Parts by weight polymethyl methacrylate (20%) 9.0 parts by weight methyl isobutyl ketone 28.0 parts by weight methyl ethyl ketone 13.0 parts by weight

Composition of coating liquid 5 for forming layer A PET-30 25.0 parts by mass DPHA 15.0 parts by mass MX-600 (translucent fine particles) 0.30 parts by mass SSX106FB (translucent fine particles) 0.30 parts by mass Irgacure 127 1.6 parts by mass SP-13 0.14 parts by mass Polymethyl methacrylate (20%) 3.5 parts by mass Methyl isobutyl ketone 32.0 parts by mass Methyl ethyl ketone 11.0 parts by mass

Composition of coating liquid 6 for forming layer A PET-30 27.0 parts by mass DPHA 15.0 parts by mass MX-600 (translucent fine particles) 0.19 parts by mass SSX106FB (translucent fine particles) 0.33 parts by mass Irgacure 127 1.5 parts by mass SP-13 0.14 parts by mass Polymethyl methacrylate (20%) 9.0 parts by mass KBM-5103 6.0 parts by mass Methyl isobutyl ketone 28.0 parts by mass Methyl ethyl ketone 13.0 parts by mass

Composition of coating liquid 1 for overcoat layer formation (layer refractive index 1.54, surface refractive index 1.54)
PET-30 32.9 parts by mass Irgacure 127 1.1 parts by mass SP-13 0.1 parts by mass Methyl isobutyl ketone 46.1 parts by mass Methyl ethyl ketone 20.0 parts by mass

Composition of coating liquid 2 for overcoat layer formation (layer refractive index 1.52, surface refractive index 1.52)
PET-30 21.7 parts by mass Irgacure 127 1.1 parts by mass SP-13 0.1 parts by mass Sol solution a 11.2 parts by weight Methyl isobutyl ketone 46.1 parts by mass Methyl ethyl ketone 20.0 parts by mass

For the coating solution for forming layer A, the translucent fine particles are made into a 30% by mass methyl isobutyl ketone solution, dispersed at 10,000 rpm for 20 minutes in a polytron disperser, and then other components are added so as to achieve the above composition ratio. To prepare a coating solution. The coating solution was filtered through a polypropylene filter having a pore diameter of 30 μm to prepare coating solutions 1 to 6 for forming layer A.
Moreover, about the coating liquid for overcoat layer formation, the component was added so that it might become the said composition ratio, and the coating liquid was prepared. The coating solution was filtered through a polypropylene filter having a pore size of 30 μm to prepare coating solutions 1 and 2 for forming an overcoat layer.

The compounds used are shown below.
KBM-5103: Silane coupling agent [Shin-Etsu Chemical Co., Ltd.]
DPHA: Mixture of dipentaerythritol pentaacrylate and dipentaerythritol hexaacrylate [manufactured by Nippon Kayaku Co., Ltd.]
PET-30: A mixture of pentaerythritol triacrylate and pentaerythritol tetraacrylate [manufactured by Nippon Kayaku Co., Ltd.]
・ Irgacure 127: Polymerization initiator [Ciba Specialty Chemicals Co., Ltd.]
-Polymethyl methacrylate (20%): a solution in which 20 parts by mass of polymethyl methacrylate powder (mass average molecular weight 120,000, manufactured by Aldrich) was dissolved in 80 parts by mass of methyl ethyl ketone. MX-150H: cross-linked polymethyl having an average particle size of 1.5 µm Methacrylate fine particles, refractive index 1.50, manufactured by Soken Chemical Co., Ltd., MX-600: average particle size 6.0 μm crosslinked polymethyl methacrylate fine particles, refractive index 1.50, manufactured by Soken Chemical Co., Ltd., MX-1000: average Particle size 10 μm crosslinked polymethyl methacrylate fine particles, refractive index 1.50, manufactured by Soken Chemical Co., Ltd. • SX-350HL: average particle size 3.5 μm crosslinked acrylic-styrene fine particles, refractive index 1.55, manufactured by Soken Chemical Co., Ltd. SSX106FB: mean particle size 6.0 μm crosslinked acrylic-styrene fine particles, refractive index 1.55, Sekisui Plastics Co., Ltd. ) Made

  In the structural formula of SP-13, “90” and “10” represent the molar ratio of repeating units.

(Preparation of optical film 101)
A triacetyl cellulose film (TAC-TD80U, manufactured by FUJIFILM Corporation, thickness 80 μm) is unwound from the roll form, and the coating liquid 1 for forming layer A is prepared using a coater having a slot die and a slide shown in FIG. The slot 16 and overcoat layer forming coating solution 1 were directly extruded by a slide 51 and applied. After coating at a transfer speed of 30 m / min, drying at 30 ° C. for 15 seconds and 90 ° C. for 20 seconds, and further using a 160 W / cm air-cooled metal halide lamp (made by Eye Graphics Co., Ltd.) under a nitrogen purge. The coating layer was cured by irradiating ultraviolet rays with an irradiation amount of 90 mJ / cm ² to form a layer A having an average film thickness of 1.8 μm and an overcoat layer having an average film thickness of 6.0 μm, thereby producing an optical film 101.
In this example, the “layer refractive index” and “surface refractive index” of the overcoat layer were measured as follows. Each overcoat layer-forming coating solution is independently applied on a triacetyl cellulose film (TAC-TD80U, manufactured by Fuji Film Co., Ltd., thickness 80 μm), and other conditions are layers in an optical film sample using the coating solution. Only the overcoat layer is formed under the same conditions as the formation conditions, and the average refractive index of the entire layer and the average refractive index of the region from the surface to 100 nm are measured, and “layer refractive index” and “surface refractive index”, respectively. It was. (The same applies hereinafter.) The refractive index was measured using a reflection spectral film thickness meter “FE-3000” (manufactured by Otsuka Electronics Co., Ltd.) utilizing light interference.

(Production of optical films 102-108, 110)
In the production of the optical film 101, the optical films 102 to 108, the coating liquid for forming the layer A, the coating liquid for forming the overcoat layer, and the respective film thicknesses were changed as shown in Table 1, 110 was produced.

(Preparation of optical film 109)
In the production of the optical film 101, the coating liquid for forming the layer A and the coating for forming the overcoat layer were changed as shown in Table 1, dried at 90 ° C. for 20 seconds, and then heated at 110 ° C. for 10 minutes. An optical film 109 was produced in the same manner as the optical film 101 except that it was cured.

(Preparation of optical film 111)
A triacetyl cellulose film (TAC-TD80U, manufactured by Fuji Film Co., Ltd., thickness 80 μm) was unwound from the roll form, and the coating solution 4 for forming layer A was extruded and applied using a coater having a slot die. After coating at a transfer speed of 30 m / min, drying at 30 ° C. for 15 seconds and 90 ° C. for 20 seconds, and further using a 160 W / cm air-cooled metal halide lamp (made by Eye Graphics Co., Ltd.) under a nitrogen purge. The coating layer was cured by irradiating with an ultraviolet ray having an irradiation amount of 90 mJ / cm ² to form a layer A having an average film thickness of 0.5 μm. On the layer A, the overcoat layer forming coating solution 1 was applied by extrusion using a coater having a slot die. After coating at a transfer speed of 30 m / min, drying at 30 ° C. for 15 seconds and 90 ° C. for 20 seconds, and further using a 160 W / cm air-cooled metal halide lamp (made by Eye Graphics Co., Ltd.) under a nitrogen purge. The coating layer was cured by irradiating with an ultraviolet ray with an irradiation amount of 90 mJ / cm ² to form an overcoat layer with an average film thickness of 1.5 μm, and an optical film 111 was produced.

(Preparation of optical film 112)
A triacetyl cellulose film (TAC-TD80U, manufactured by Fuji Film Co., Ltd., thickness 80 μm) was unwound from the roll form, and the coating solution 1 for forming layer A was extruded and applied using a coater having a slot die. It apply | coated on conditions with a conveyance speed of 30 m / min. The overcoat layer forming coating solution 1 was applied onto the coating layer of the layer A forming coating solution 1 by using a coater having a slot die. After coating at a transfer speed of 30 m / min, drying at 30 ° C. for 15 seconds and 90 ° C. for 20 seconds, and further using a 160 W / cm air-cooled metal halide lamp (made by Eye Graphics Co., Ltd.) under a nitrogen purge. The coating layer was cured by irradiating with an ultraviolet ray with an irradiation amount of 90 mJ / cm ² to form a layer A having an average film thickness of 1.8 μm and an overcoat layer having an average film thickness of 6.0 μm, whereby an optical film 112 was produced.

  In addition, the average film thickness of the layer A and the overcoat layer is a layer formed by applying each layer-forming coating solution on the support alone, and curing under the same conditions as the actually produced optical film. The average film thickness.

(Evaluation of optical film)
Various characteristics of the produced optical film were evaluated by the following methods. The results are shown in Tables 1 and 2.
In addition, the average distance h between the center of the translucent fine particles in the antiglare layer and the support side interface is observed by enlarging the cross section of the film 500 times using an optical microscope, and the average value of 100 translucent fine particles. Calculated as
Further, the average distance l of the light-transmitting fine particles adjacent to each other in the in-plane direction of the anti-glare layer is magnified 200 times using a light microscope under transmitted light, and the film is observed. The distance from each closest translucent fine particle was measured and calculated as an average value of 30 particles.
In Table 1, the thicknesses of h and l and the antiglare layer are described as a ratio (1 / r) to the average particle diameter r of the light-transmitting fine particles.

(Black tightening when displaying black <Black reproducibility>)
A polarizing film was prepared by adsorbing iodine to a stretched polyvinyl alcohol film. Each of the optical films 101 to 112 was saponified, and was attached to one side of the polarizing film using a polyvinyl alcohol-based adhesive so that the triacetyl cellulose side of each optical film was the polarizing film side. Also, a commercially available triacetyl cellulose film “Fujitac TD80UF” {manufactured by Fuji Film Co., Ltd.} is attached to the side of the polarizing film opposite to the side on which the optical films 101 to 112 are pasted using a polyvinyl alcohol adhesive. It was. In this manner, polarizing plates (HKH-01) to (HKH-12) with optical films 101 to 112 were produced.
32-inch full high-definition liquid crystal TV “LC-32GS10” {manufactured by Sharp Corporation, pixel size 370 μm} is peeled off the polarizing plate on the viewing side, and polarizing plates (HKH-01) to (HKH-12) are used instead of the optical film Attached to the viewing side through an adhesive so that becomes the outermost surface. In general, the panel was driven with a black display in a general home environment (about 200 Lx) using a TV, and a white-brown feeling was visually confirmed. The criteria for visual inspection are: ◎ when black is jet black and very good, ○ when black is good, slightly browned, △ when not interested, whitedish The case where it is “×” and the case where Δ is more than “good” were accepted.

(Reflection: Anti-glare)
After the back surfaces of the optical films 101 to 112 were painted with black magic, the state of reflection of light when the fluorescent light was reflected on the film surface was evaluated.
○: Reflection is sufficiently suppressed, or light is sufficiently diffused, so there is no concern.
Δ: The shape of the fluorescent lamp is slightly reflected, but I do not care.
X: The shape of the fluorescent light is clearly reflected, and it is dazzling and worrisome.
A level of △ or higher was determined to be acceptable.

(Layer A and overcoat layer interface observation)
Taking each optical film as a 50 nm thick slice, the cross section was photographed 150,000 times using a transmission electron microscope, and the mixing of the interface between the layer A and the overcoat layer in the antiglare layer was observed. did. In Table 2, “clear” means that the presence of the interface between the layer A and the overcoat layer was not confirmed by observation, and “mixed” means that the presence of the interface was not confirmed by observation.

(Adhesion test)
The obtained film sample was subjected to a cross cut tape peeling test in accordance with JIS D0202-1988. Using cellophane tape (“CT24”, manufactured by Nichiban Co., Ltd.), the film was adhered to the film with the belly of the finger and then peeled off. Judgment is represented by the number of squares that do not peel out of 100 squares. The case where the functional layer does not peel is represented as 100/100, and the case where the functional layer peels completely is represented as 0/100.

(Interference unevenness)
When the three-wavelength fluorescent lamp was reflected in the dark room after the back surfaces of the optical films 101 to 112 were painted with black magic, the edge portion of the reflected fluorescent lamp image was visually evaluated according to the following criteria.
○: Iridescent unevenness does not occur at the edge of the fluorescent lamp.
X: Iridescent unevenness occurs.

(Evaluation of point defects due to coarse particles)
In the optical films 101-112, the point defect by the coarse particle was counted by visual observation with the transmitted light in the range of 1.34 m × 5.00 m.
○: Less than one.
Δ: 1 or more and less than 2
X: Two or more △ or more levels were judged to be acceptable.

  The evaluation results are shown in Tables 1 and 2.

From the above results, an optical film having an antiglare layer containing a binder and translucent fine particles, wherein the average particle size of the translucent fine particles is 3 μm or more and 15 μm or less, and the average film thickness of the antiglare layer is translucent. An optical film having an average particle diameter larger than the average particle diameter and having an average distance h of not less than 0.5 and not more than 0.6 has good black tightening, little reflection, good adhesion, interference unevenness and translucent fine particles. It turned out that it is an excellent optical film in which the point defect by a coarse particle is hard to visually recognize.
In addition, in comparison with the films 104 and 111, when the layer A forming coating solution and the overcoat layer forming coating solution are simultaneously applied to form a layer A and an overcoat layer (in the case of simultaneous multilayer application: film 104). Compared with the case where the overcoat layer was formed by applying an overcoat layer forming coating solution on the layer A after forming the layer A, the adhesion, interference unevenness, It turned out to be excellent in terms of point defects. This is presumed to be because the layer interface between the layer A and the overcoat layer is mixed in the case of simultaneous multilayer coating.

[Example 2]
The following coating liquids 3-7 for forming an overcoat layer were prepared.

Composition of coating liquid 3 for overcoat layer formation (layer refractive index 1.54, surface refractive index 1.54)
PET-30 31.9 parts by weight Irgacure 127 1.1 parts by weight SP-13 0.1 part by weight X22-164C 1.0 part by weight Methyl isobutyl ketone 46.1 parts by weight Methyl ethyl ketone 20.0 parts by weight

  In place of X22-164C of overcoat forming coating solution 3, those using RMS-033, MCF-323, and OPTOOL DAC were applied to overcoat layer forming coating solutions 4 to 6 (layer refractive index 1.545, surface The refractive index is 1.54).

Composition of overcoat layer forming coating solution 7 (layer refractive index 1.52, surface refractive index 1.51)
PET-30 25.6 parts by mass Irgacure 127 1.1 parts by weight SP-13 0.1 parts by weight Optool DAC 1.0 part by weight Conductive particles 6.3 parts by weight Methyl isobutyl ketone 46.1 parts by weight Methyl ethyl ketone 20.0 Parts by mass

Details of the compounds used are shown below.
-X22-164C: (Both-ends methacryl-modified dimethylsiloxane, average molecular weight of about 5000, manufactured by Shin-Etsu Chemical Co., Ltd.)
RMS-033: (acryl-modified dimethylsiloxane, average molecular weight of about 25000, manufactured by Gelest)
MCF-323: Defender MCF-323 Non-fluoroether type fluorosurfactant (manufactured by Dainippon Ink & Chemicals, Inc.)
-OPTOOL DAC: UV curable antifouling additive containing perfluoropolyether (Daikin Chemical Industries, Ltd.)
・ Conductive particles:
(Antimony oxide-coated silica fine particles prepared according to Example 1 of JP-A-2005-119909, 20% isopropyl alcohol dispersion, average particle size 60 nm, refractive index 1.41, volume resistance 1500 Ω · cm, per inorganic particle solid content 4% methacrylic silane coupling agent (Shin-Etsu Chemical Co., Ltd .: KBM-503) surface treatment)

(Production of optical films 113 to 117)
Optical films 113 to 117 were prepared in the same manner as the optical film 101 except that the optical film 101 was changed to the overcoat layer coating solutions 3 to 7, respectively. The translucent fine particle content in the antiglare layer of the optical films 113 to 117 is as follows: film 113: 0.23% by mass, film 114: 0.23% by mass, film 115: 0.23% by mass, film 116: 0. They were 23 mass% and film 117: 0.23 mass%. As a result of the same evaluation as in Example 1, the manufactured optical films 113 to 117 had good black tightening, little reflection, good adhesion, and point defects due to interference unevenness / transparent fine particles were visually recognized. It turned out to be an excellent and difficult optical film.

(Surface free energy)
The contact angle was measured with pure water and methylene iodide under the conditions of 25 ° C. and 60 RH%. K. Owens: J.M. Appl. Polym. Sci. , 13, 1741 (1969), the surface free energy (γsv: unit, mN / m) was calculated. It was found that the optical film 101 was 40 mN / m, and the optical films 113 to 117 were 30 mN / m or less.

(Anti-fouling durability)
The optical films 101 and 113 to 117 are fixed on the glass surface with an adhesive, and the diameter is 5 mm with a pen tip (thin) of black magic “Mackey extra fine (product name: manufactured by ZEBRA)” under conditions of 25 ° C. and 60 RH%. Write a circle three times and wipe it back and forth 20 times with a load that dents the bundle of Bencot with a Bencot (trade name, Asahi Kasei Co., Ltd.) that is folded into 10 layers after 5 seconds.
The writing and wiping were repeated under the above conditions until the magic traces were not erased by wiping, and the antifouling property was evaluated by the number of times that the wiping was completed. While the number of times until the optical film 101 does not disappear is one, the number of times until the optical films 113 to 117 all disappear is 10 times or more, and the antifouling durability is excellent. In particular, the optical films 115 and 116 are 30 times or more and have excellent antifouling durability.

(Dust removal)
The optical films 116 and 117 of the present invention were attached to a monitor, dust (a garment, fiber waste from clothes) was sprinkled on the monitor surface, the dust was wiped off with a cleaning cloth, and the dust removal property was evaluated. The optical film 116 can be removed by wiping 10 times, whereas the optical film 117 is a film having excellent dust removing properties that can be completely removed by wiping 3 times.

[Example 3]
The following overcoat layer forming coating solution 8 was prepared.

Composition of overcoat layer forming coating solution 8 (layer refractive index 1.52, surface refractive index 1.39)
PET-30 30.0 parts by mass Irgacure 127 1.1 parts by mass SP-13 0.1 parts by mass MEK-ST-L 0.5 parts by mass Low refractive index silica 5.0 parts by mass Methyl isobutyl ketone 43.1 parts by mass Methyl ethyl ketone 19.0 parts by mass

Details of the compounds used are shown below.
MEK-ST-L: (Colloidal silica, average particle diameter of about 50 nm, solid content of 30%, methyl ethyl ketone dispersion, manufactured by Nissan Chemical Co., Ltd.)
Low refractive index silica: (silica having a diameter of about 60 nm, voids inside, refractive index 1.25, 3% trimethylmethoxysilane and 7% acryloyloxypropyltrimethoxysilane as a surface treatment agent, solid content 33% , Methyl isobutyl ketone dispersion, prepared by changing the size according to Example 4 of JP-A-2002-79616)

(Preparation of optical film 118)
An optical film 118 was produced in the same manner as the optical film 101 except that the optical film 101 was changed to the overcoat layer coating solution 8 in the production of the optical film 101. The translucent fine particle content in the antiglare layer of the optical film 118 was 0.23% by mass. As a result of performing the same evaluation as in Example 1, the manufactured optical film 118 has good black tightening, little reflection, good adhesion, and excellent visibility of point defects due to interference unevenness and coarse particles of translucent fine particles. It was found to be an optical film.

(Integral reflectance)
The back surface of the optical film 118 (surface opposite to the side having the low refractive index layer of the triacetyl cellulose film as a support) is roughened with sandpaper and then treated with black ink to eliminate back surface reflection. I made it. The surface of the antireflection film is attached to an integrating sphere of a spectrophotometer V-550 (manufactured by JASCO Corporation), and the reflectance (integrated reflectance) is measured in a wavelength region of 380 to 780 nm. An average reflectance of ˜650 nm was calculated, and antireflection properties were evaluated. The reflectivity was 3.2%, and the high reflectivity was 1% lower than the optical film 101 of 4.3%, and the antireflection performance was excellent.

[Example 4]
In Example 1, a sample in which the thickness of the support was changed to a 40 μm triacetyl cellulose film was prepared. As a result of performing the same evaluation as in Example 1, the manufactured optical film had good black tightening, less reflection, good adhesion, and excellent in the point defect due to interference unevenness and coarse particles of translucent fine particles. It was found to be an optical film.

[Example 5]
(Coating of low refractive index layer)
(Preparation of coating solution A for low refractive index layer)
Hollow silica particle fine particle sol (isopropyl alcohol silica sol, CS60-IPA manufactured by Catalytic Chemical Industry Co., Ltd., average particle diameter 60 nm, shell thickness 10 nm, silica concentration 20%, silica particle refractive index 1.31) in 500 parts, acryloyloxy After 20 parts of propyltrimethoxysilane and 1.5 parts of diisopropoxyaluminum ethyl acetate were added and mixed, 9 parts of ion-exchanged water was added. After reacting at 60 ° C. for 8 hours, the mixture was cooled to room temperature, and 1.8 parts of acetylacetone was added to obtain a dispersion. Then, while adding cyclohexanone so that the silica content was substantially constant, the solvent was replaced by distillation under reduced pressure at a pressure of 30 Torr. Finally, a dispersion having a solid content concentration of 18.2% was obtained by adjusting the concentration. The amount of IPA remaining in the obtained hollow silica particle dispersion was analyzed by gas chromatography and found to be 0.5% or less.

  A coating liquid A for a low refractive index layer having the following composition was prepared using the obtained hollow silica particle dispersion. The refractive index after curing of the low refractive index layer obtained by coating and curing the coating solution was 1.36.

Composition of coating liquid A for low refractive index layer DPHA 1.0 part by mass P-1 1.6 part by mass Hollow silica particle dispersion (18.2%) 26.4 parts by mass RMS-033 0.4 part by mass Irgacure 907 0.3 parts by mass M-1 1.9 parts by mass MEK 168.4 parts by mass

"P-1": fluorine-containing copolymer P-3 described in JP-A-2004-45462 (weight average molecular weight of about 50,000)
DPHA: a mixture of dipentaerythritol pentaacrylate and dipentaerythritol hexaacrylate, manufactured by Nippon Kayaku Co., Ltd. Irgacure 907: polymerization initiator (manufactured by Ciba Geigy Japan)
M-1: Reactive silicone compound

RMS-033: Methacryloxy-modified silicone (manufactured by Gelest Co., Ltd.)

  The coating liquid for the low refractive index layer was directly extruded using a coater having a slot die and applied to the overcoat layer side of the optical films 101 to 112 to prepare optical films 201 to 212.

The low refractive index layer was dried at 60 ° C. for 60 seconds, and the ultraviolet curing condition was 240 W / cm air-cooled metal halide lamp (eye graphics) while purging with nitrogen so that the atmosphere had an oxygen concentration of 0.1% by volume or less. Illuminance 600 mW / cm ² , irradiation amount 600
The irradiation amount was mJ / cm ² .

  The produced optical films 201 to 212 were evaluated in the same manner as in Examples 1 and 3. The evaluation results are shown in Table 3.

  It was found that the optical film of the present invention is an excellent optical film with good black tightening, less reflection, good adhesion, and it is difficult to visually recognize point defects due to uneven interference and coarse particles of translucent fine particles. Moreover, translucent fine particle contains 2.0-10.0 mass% with respect to the total solid which forms a glare-proof layer, and the average film thickness of layer A is 0.20 of the average particle diameter of translucent fine particle. The optical film which is 0.40 times and the average film thickness of the overcoat layer is 0.80 to 1.50 times the average particle diameter of the translucent fine particles has an integrated reflectance of 2.0% or less. The black tightening was found to be good.

[Example 6]
The following coating liquid B for low refractive index layer was prepared.

Composition of coating liquid B for low refractive index layer DPHA 1.7 parts by mass Irgacure 907 0.1 parts by mass PMA-ST 2.6 parts by mass CAB-531-1 0.2 parts by mass Methyl ethyl ketone 95.4 parts by mass

Details of the compounds used are shown below.
PMA-ST: (Colloidal silica, average particle size of about 15 nm, solid content of 30%, fluoropolyethylene monomethyl ether acetate dispersion, manufactured by Nissan Chemical Co., Ltd.)
CAB-531-1: cellulose acetate butyrate [Eastman Chemical Co., Ltd.]

(Preparation of optical film 119)
In the production of the optical film 201, an optical film 119 was produced in the same manner as the optical film 201 except that the coating liquid B for the low refractive index layer was changed. As a result of performing the same evaluation as in Example 5, the manufactured optical film 119 has good black tightening, little reflection, good adhesion, and it is difficult to visually recognize point defects due to interference unevenness and coarse particles of translucent fine particles. It was found to be an optical film.

[Example 7]
An optical film 101-119 and an 80 μm thick triacetyl cellulose film (TAC-TD80U, manufactured by Fuji Film Co., Ltd.) were immersed in a 1.5 mol / L, 55 ° C. NaOH aqueous solution for 2 minutes, and then neutralized and washed with water. Each of the saponified optical films 101 to 119 and the saponified triacetyl cellulose film having a thickness of 80 μm (TAC-TD80U, manufactured by Fuji Film Co., Ltd.) was allowed to adsorb iodine to polyvinyl alcohol and stretched. A polarizing plate was prepared by adhering and protecting both sides of the polarizing film prepared in this manner. The polarizing plate produced in this manner was used for a liquid crystal display device of a notebook personal computer equipped with a transmission type TN liquid crystal display device (Sumitomo 3M Co., Ltd., which is a polarization separation film having a polarization selection layer) so that the low refractive index layer is the outermost surface. When the polarizing plate on the viewing side of (having D-BEF made between) and the liquid crystal cell) is pasted, the optical film of the present invention has very little background reflection and very high display quality. A display device was obtained. Moreover, the optical film of this invention was not able to visually recognize a point defect.

[Example 8]
When each film of the sample of the present invention in Example 1 was bonded to the glass plate on the surface of the organic EL display device via an adhesive, reflection on the glass surface was suppressed, and a display device with high visibility was obtained. It was. Moreover, the optical film of this invention was not able to visually recognize a point defect.

[Example 9]
Using each film of the sample of the present invention in Example 1, a polarizing plate having the optical film of the present invention on one side was prepared, and λ / on the opposite side of the polarizing plate having the optical film of the present invention. When the four plates are bonded together and attached to the glass plate on the surface of the organic EL display device so that the optical film side of the present invention is the outermost surface, the surface reflection and the reflection from the inside of the surface glass are cut off and extremely visible. High display was obtained. Moreover, the optical film of this invention was not able to visually recognize a point defect.

10 Coater 11 Backup Roll W Web 13 Slot Die 14 Coating Solution 14a Bead 14b Coating 15 Pocket 16 Slot 16a Slot Opening 17 Tip Lip 18 Land 18a Upstream Lip Land 18b Downstream Lip Land 50, 52 Pocket 51, 53 Slide 55 cover

Claims (14)

An optical film having an antiglare layer containing a binder and translucent fine particles on a support,
The translucent fine particles have an average particle diameter r of 3 μm or more and 15 μm or less,
The content of the translucent fine particles in the antiglare layer is 0.1% by mass or more and 1.0% by mass or less based on the total solid content of the antiglare layer,
The average film thickness of the antiglare layer is larger than the average particle diameter r of the translucent fine particles, and the average distance between the center of the translucent fine particles and the interface of the antiglare layer near the support is h. Then, the average distance h and the average particle diameter r of the translucent fine particles satisfy the following formula 1.
Formula 1: r × 0.5 ≦ h ≦ r × 0.6   2. The optical film according to claim 1, wherein an average film thickness of the antiglare layer is 1.01 times or more and 2.00 times or less of an average particle diameter r of the translucent fine particles.   The average distance of the said translucent fine particle adjacent in the said glare-proof layer is 1.5 times or more and 10 times or less of the average particle diameter r of the said translucent fine particle, The Claim 1 or 2 characterized by the above-mentioned. The optical film as described.   The antiglare layer further contains inorganic fine particles, and the inorganic fine particles exist on the side farther from the support in the film thickness direction of the antiglare layer. The optical film as described.   The optical film according to claim 4, wherein the inorganic fine particles are inorganic fine particles mainly composed of silica having an average particle diameter of 1 nm to 1 μm.   The optical film according to claim 4 or 5, wherein the inorganic fine particles have pores on at least one of the surface and the inside of the particles.   The optical film according to claim 4, wherein the inorganic fine particles are conductive particles.   The antiglare layer further contains at least one kind of reactive silicone and reactive fluorine compound, and at least one kind of the reactive silicone and reactive fluorine compound is only on the side far from the support in the film thickness direction of the antiglare layer. The optical film according to claim 1, wherein the optical film is present.   The surface free energy of the said glare-proof layer is 30 mN / m or less, The optical film as described in any one of Claims 1-8 characterized by the above-mentioned.   10. The optical film according to claim 1, wherein a surface refractive index of the antiglare layer is 1.25 or more and 1.49 or less.   The thickness of the said support body is 15 micrometers or more and 60 micrometers or less, The optical film as described in any one of Claims 1-10 characterized by the above-mentioned.   The optical film according to claim 1, further comprising a low refractive index layer on the antiglare layer.   A polarizing plate having a polarizing film and protective films on both sides of the polarizing film, wherein at least one of the protective films is the optical film according to claim 1. Polarizing plate.   An image display device comprising the optical film according to claim 1 or the polarizing plate according to claim 13.

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