WO2012164843A1 - Antiglare film, method for producing same, polarizing plate, image display device, member for touch panel - Google Patents

Abstract

One embodiment of the present invention is an antiglare film having an antiglare film disposed on top of a substrate film, the antiglare film being characterized in that the arithmetic average roughness Ra (nm) of the surface of the antiglare layer and the correlation length Ic (µm) as defined by the following definitional equation satisfy the following relational equation (1). Relational equation (1): 0 ≤ Ic ≤ 21-8×exp((215-Ra)/40)-13×exp((215-Ra)/400) Definitional equation: Correlation length Ic = root mean square roughness Rq (µm)/root mean square gradient ∆q × 2^1/2

Description

Antiglare film, method for producing the same, polarizing plate, image display device, and touch panel member

The present invention relates to an antiglare film and a method for producing the same. The present invention also relates to a polarizing plate, an image display device, and a touch panel member provided with the antiglare film.

In an image display device such as a liquid crystal display device, the surface of the image display unit is anti-glare to prevent the visibility from being disturbed by a ghost phenomenon in which illumination light such as a fluorescent lamp or the sun or an external light beam is reflected on the screen. It is common to provide a layer.

Recently, when an anti-glare film having an anti-glare layer is used as it is in a high-definition or color image display device, there has been a problem that moire fringes are generated on the display screen.

For example, Patent Documents 1 and 2 disclose techniques for improving the moire fringe problem. The technique is a technique for reducing the occurrence of moire fringes by adjusting the arrangement direction of the fine uneven structure of the antiglare film, the arrangement direction of the display elements, and the like.

Specifically, the techniques disclosed in Patent Documents 1 and 2 are such that, first, a shaping roll is pressed against the antiglare layer to which fine particles are added at a specific angle to form fine irregularities on the antiglare layer, and the resin and fine particles The antiglare property is imparted to the antiglare layer by the internal scattering due to the difference in refractive index between and the surface scattering due to the fine unevenness of the antiglare layer. Furthermore, the fine unevenness of the antiglare layer is adjusted to a specific angle. By doing so, the generation of moire fringes is reduced.

On the other hand, a prism sheet is used in the liquid crystal display device in order to condense the backlight to the front. There is also a problem that moire fringes occur due to the surface shape of the prism sheet. In order to improve the problem of moire fringes due to this prism sheet, when the antiglare film described in Patent Documents 1 and 2 is used for the polarizing plate on the rear side, the occurrence of moire fringes is reduced, but the front luminance is reduced. A problem has occurred. When the front luminance decreases, the screen of the liquid crystal display device becomes dark, and there is a problem of visibility deterioration due to a decrease in contrast.

JP 2003-4917 A Japanese Patent Laid-Open No. 2003-5661

The present invention has been made in view of the above-described problems and situations, and an object thereof is to provide an antiglare film capable of achieving both improvement in visibility and reduction of moire fringes and a method for producing the same. And Another object of the present invention is to provide a polarizing plate, an image display device, and a touch panel member provided with the antiglare film.

The above-mentioned problem according to the present invention is solved by the following means.

One aspect of the present invention is an antiglare film having an antiglare layer on a substrate film, and the arithmetic average roughness Ra (nm) of the surface of the antiglare layer and a correlation defined by the following defining formula: The antiglare film is characterized in that the length Ic (μm) satisfies the following relational expression (1).
Relational expression (1): 0 ≦ Ic ≦ 21−8 × exp ((215−Ra) / 40) −13 × exp ((215−Ra) / 400)
Definition formula: Correlation length Ic = root mean square roughness Rq (μm) / root mean square slope Δq × 2 ^1/2

Another aspect of the present invention is a method for producing an antiglare film for producing the antiglare film, wherein the viscosity at 25 ° C. is in the range of 20 to 3000 mPa · s. And an antiglare layer coating composition containing at least one solvent selected from the group consisting of esters, glycol ethers, and alcohols, a coating step of coating on a base film, and a decreasing rate drying section Maintaining the temperature within a range of 90 to 160 ° C., drying the antiglare layer coating composition, and curing the dried antiglare layer coating composition to prevent the antiglare layer coating on the base film. It is a manufacturing method of the anti-glare film characterized by including the hardening process which forms a glare layer.

The objects, features, aspects and advantages of the present invention will become more apparent from the following detailed description and the accompanying drawings.

FIG. 1 is an explanatory diagram of protrusions. FIG. 2 is a schematic view showing irregular protrusions of the antiglare layer of the antiglare film according to one embodiment of the present invention. FIG. 3 is an observation view showing the result of observing the antiglare layer surface of the antiglare film according to Example 1 with an optical interference surface roughness meter. FIG. 4 is a cross-sectional view of a polarizing plate according to another embodiment of the present invention. FIG. 5 is a cross-sectional view of the liquid crystal panel produced in the example. FIG. 6 is a schematic view of a liquid crystal cell of a liquid crystal display device. FIG. 7 is a diagram illustrating a configuration example of an antiglare film with a conductive film. FIG. 8 is a schematic diagram illustrating an example of a configuration of a resistive film type touch panel liquid crystal display device.

An anti-glare film according to an embodiment of the present invention is an anti-glare film having an anti-glare layer on a base film, and the arithmetic average roughness Ra (nm) of the surface of the anti-glare layer and the above definition formula The correlation length Ic (μm) defined by the above satisfies the relational expression (1). This feature is a technical feature common to other embodiments of the present invention.

In the antiglare film, it is preferable that the arithmetic average roughness Ra of the surface of the antiglare layer and the correlation length satisfy the following relational expression (2) from the viewpoint of manifesting the effects of the present invention.

The antiglare film preferably has an arithmetic average roughness Ra of the surface of the antiglare layer in the range of 350 to 1300 nm.

The antiglare film preferably has a haze due to internal scattering of the antiglare layer in the range of 0 to 0.5%.

In the antiglare film, the antiglare layer preferably contains an actinic radiation curable resin having a viscosity at 25 ° C. in the range of 20 to 3000 mPa · s.

In the antiglare film, it is preferable that the antiglare layer contains fine particles and does not substantially contain a resin that is incompatible with the fine particles and the actinic radiation curable resin.

In the antiglare film, the surface of the antiglare layer preferably has an irregular protrusion shape having no period in the longitudinal direction.

Another embodiment of the present invention is a method for producing an antiglare film for producing the antiglare film, wherein the viscosity at 25 ° C. is in the range of 20 to 3000 mPa · s. A coating step for coating an antiglare layer coating composition containing a resin and at least one solvent selected from the group consisting of esters, glycol ethers, and alcohols on a base film; And maintaining the temperature within a range of 90 to 160 ° C. to dry the antiglare layer coating composition, and curing the dried antiglare layer coating composition onto the base film. It is a manufacturing method of the anti-glare film characterized by including the hardening process which forms an anti-glare layer.

The antiglare film according to the present embodiment can be suitably included in a polarizing plate, an image display device, and a touch panel member.

Hereinafter, embodiments according to the present invention will be described, but the present invention is not limited thereto.

In this application, “˜” is used to mean that the numerical values described before and after it are included as a lower limit value and an upper limit value. The “surface haze value” and the “internal haze value” are also simply expressed as “surface haze” and “internal haze”, respectively.

(Outline of antiglare film)
The term “antiglare film” as used in the present application refers to a layer that blurs the outline of a reflected image or external light, that is, an antiglare layer on the surface of a film substrate, so that a liquid crystal display, an organic EL display, a plasma display, etc. It refers to a film that suppresses reflection of external light and reflected images when an image display device is used.

<Surface shape>
An antiglare film according to an embodiment of the present invention is an antiglare film having an antiglare layer on a base film, and the arithmetic average roughness Ra (nm) of the surface of the antiglare layer and the following definition formula: The correlation length Ic (μm) defined by the above satisfies the following relational expression (1).
Relational expression (1): 0 ≦ Ic ≦ 21−8 × exp ((215−Ra) / 40) −13 × exp ((215−Ra) / 400)
Definition formula: Correlation length Ic = root mean square roughness Rq (μm) / root mean square slope Δq × 2 ^1/2

Such an antiglare film can achieve both improved visibility and reduced moire fringes.

Here, “arithmetic mean roughness (Ra)”, “root mean square roughness (Rq)” and “root mean square slope (Δq)” of the surface of the antiglare layer are described in JIS B0601: 1994. It conforms to the definition etc. That is, the arithmetic average roughness (Ra) of the roughness curve obtained for the surface of the antiglare layer based on the JIS standard. Specifically, it can be determined by the following method.

First, according to JIS B0601: 1994, the surface state of the anti-glare layer was determined by using an optical interference surface roughness meter (for example, RST / PLUS, WYKO, New View 5030, manufactured by Zygo). In the embodiment, about 0.36 mm × 0.27 mm) is measured, and a surface shape map is created. This map is, for example, an image of 320 pixels × 240 pixels, and is roughness curved surface data holding height data in each pixel.

For example, the arithmetic average roughness (Ra) is obtained by adding and averaging the absolute value of the height deviation from the average surface of this map to the roughness curve for all pixels.

The root mean square roughness (Rq) is obtained by summing the squares of height deviations for all pixels and averaging them, and taking the square root.

The root mean square slope (Δq) is obtained by summing the squares of slope data of adjacent pixels for all the pixels and taking the square root.

As an embodiment of the present invention, from the viewpoint of the effect of the present invention, the arithmetic average roughness Ra (nm) and the correlation length Ic (μm) of the surface of the antiglare layer satisfy the following relational expression (2). It is preferable.
Relational expression (2): 0 ≦ Ic ≦ 17−6 × exp ((225−Ra) / 40) −11 × exp ((225−Ra) / 400)

Note that the right side of the relational expression (1) and the relational expression (2) (expression expressed by an exponential function) is a method for calculating the scattering intensity of light on a random uneven surface in consideration of the wave nature of light (“light / radio wave”). It is an approximate curve of a curve obtained by plotting points at which the light intensity in the linear transmission direction is below a certain value according to “Basics of Analysis” (see Corona). On the uneven surface where the roughness is not so large, there is a component that is not substantially scattered by the uneven surface due to the wave nature of light. If the intensity of this component is below a certain value, the degree of elimination of moire fringes (moire) It shows that the reduction degree of fringes is high.

In the present embodiment, the arithmetic average roughness Ra of the surface of the antiglare layer is preferably in the range of 350 to 1300 nm. More preferably, it is in the range of 400 to 1000 nm. By making it within such a range, the generation of moire fringes can be further reduced. Therefore, the elimination of moire fringes can be further improved. That is, the problem of moire fringes can be solved more.

In the present embodiment, it is preferable from the viewpoint of visibility that the surface of the antiglare layer has an irregular protrusion shape having no period in the longitudinal direction.

In order to obtain the arithmetic average roughness Ra within the above range, the height of the protrusion shape is preferably 20 nm to 6 μm. The width of the protrusion shape is 50 nm to 300 μm, preferably 50 nm to 100 μm. The height and width of the protrusion shape can be obtained from cross-sectional observation. In order to make it easier to understand, FIG. 1 shows an explanatory view of the protrusion.

Next, the protrusion shape will be described. As shown in FIG. 1, the center line a is drawn on the cross-sectional observation image, and the distance between the two intersections of the lines b and c and the center line a forming the mountain ridge is defined as the protrusion size width t and did. Further, the distance from the summit to the center line a is obtained as the height h of the protrusion size.

In the present embodiment, the 10-point average roughness Rz of the antiglare layer of the antiglare film is preferably 10 times or less the arithmetic average roughness (centerline average roughness) Ra, and the average mountain valley distance Sm is preferably 5 to 150 μm. More preferably, it is 20 to 100 μm, the standard deviation of the height of the convex part from the deepest part of the unevenness is 0.5 μm or less, the standard deviation of the mean mountain valley distance Sm with respect to the center line is 20 μm or less, and the inclination angle is 0 to 5 degrees. The surface is preferably 10% or more. By designing in this way, an effect of suppressing white sensation can be obtained.

In this embodiment, the root mean square roughness (Rq) is preferably 400 to 1700 nm (0.4 to 1.7 μm) from the viewpoint of reducing moire fringes.

The root mean square slope (Δq) is preferably 0.01 to 0.3 from the viewpoint of suppression of white sensation.

Therefore, the correlation length is preferably 2 to 240 μm from both viewpoints.

Ra, Sm, Rz, Rq, and Δq are values measured with an optical interference surface roughness meter (for example, RST / PLUS, manufactured by WYKO, New View 5030 manufactured by Zygo) according to JIS B0601: 1994. is there.

In the antiglare film according to this embodiment, the haze caused by internal scattering of the antiglare layer is preferably in the range of 0 to 1.0%. Visibility can be further improved by being in such a range.

When forming the above-described protrusion shape, the internal haze within the above range is controlled, and the arithmetic average roughness Ra of the protrusion shape is controlled within the above range, and the antiglare layer is incompatible with the fine particles and the actinic radiation curable resin. The objective effect of this invention is exhibited favorably by not containing substantially the resin which is. The internal haze is more preferably 0 to 0.5%.

Internal haze can be measured by the following procedure. A few drops of silicone oil are dropped on the front and back surfaces of the antiglare film and sandwiched between two glass plates (micro slide glass product number S 9111, manufactured by MATSANAMI) having a thickness of 1 mm. An anti-glare film sandwiched between front and back glass is optically brought into close contact with two glass plates, and in this state, haze (Ha) is measured according to JIS-K7105 and JIS K7136. Next, a few drops of silicone oil are dropped between two glass plates and sandwiched to measure glass haze (Hb). And internal haze (Hi) is computable by drawing glass haze (Hb) from the haze (Ha) which pinched | interposed the glare-proof film with glass. Further, the surface haze (the haze resulting from the surface scattering of the film) is preferably 3 to 40%. The surface haze is obtained by subtracting the internal haze from the total haze. The total haze is preferably 3 to 40%.

The antiglare film according to the present embodiment has a protrusion shape in which the antiglare layer forms surface irregularities, the protrusion shape is a protrusion having an irregular shape in the longitudinal direction, and the arrangement thereof is also an irregular arrangement. Preferably there is. By having such a protrusion shape, the object effect of the present invention is exhibited well.

The `` irregularly shaped protrusions '' included in the antiglare layer of the antiglare film according to the present embodiment do not have a regular shape periodically in the length direction in which the surface unevenness is formed by embossing, It refers to protrusions of various shapes whose shapes and sizes are not fixed. Although not limited to these, For example, the processus | protrusion 2 of the shape formed on the surface of the glare-proof layer 1 as shown in FIG. 2 is mentioned. That is, the protrusions 2 having different widths and heights illustrated in FIG. 2 are exemplified as irregularly shaped protrusions. The “irregular arrangement” means that the irregularly-protruding protrusions are not regularly arranged (for example, at regular intervals), but are irregularly arranged at random intervals, It may be isotropic or anisotropic.

In addition, although the antiglare layer having the characteristics as described above will be described in detail later, the surface shape is, for example, controlled at a high temperature for the treatment temperature of the rate-decreasing drying section in the drying process of the antiglare layer coating composition, It can be obtained by a method in which a convection of the resin is generated, a non-uniform state is formed on the surface of the antiglare layer, and the coating is formed by curing in this non-uniform surface state. By forming the coating film by such a method, the film strength of the antiglare layer is improved. In addition to the objective effect of the present invention, the method of controlling the treatment temperature in the decreasing rate drying section in the drying process of the antiglare layer coating composition is preferable in terms of excellent productivity.

<Manufacturing method>
Moreover, the manufacturing method of the said anti-glare film will not be specifically limited if it has an anti-glare layer on a base film, and what can satisfy | fill the said relational expression (1) can be manufactured. This production method is specifically at least one selected from the group consisting of an actinic radiation curable resin having a viscosity at 25 ° C. in the range of 20 to 3000 mPa · s, esters, glycol ethers, and alcohols. An antiglare layer coating composition containing the above-mentioned solvent, and a coating process for coating the base film, and the temperature of the decreasing rate drying section is maintained within the range of 90 to 160 ° C. A manufacturing method provided with the drying process which dries a thing, and the hardening process which hardens the dried said anti-glare layer coating composition and forms an anti-glare layer on the above-mentioned substrate film is mentioned. According to such a manufacturing method, an antiglare film capable of achieving both improvement in visibility and reduction of moire fringes can be obtained. The application is not particularly limited as long as it is a method capable of applying the antiglare layer coating composition on the base film so that the thickness after curing becomes a predetermined thickness. Specifically, a coating method as described later can be used. Drying and curing are not particularly limited as long as the above conditions are satisfied and an antiglare layer can be formed on the base film, and examples thereof include the methods described below.

<Resin etc. constituting the antiglare layer>
The antiglare layer according to this embodiment preferably contains an actinic radiation curable resin having a viscosity at 25 ° C. in the range of 20 to 3000 mPa · s. By making it within such a range, it becomes easy to produce a desired surface shape. That is, the surface shape of the antiglare layer of the obtained antiglare film becomes closer to the desired shape. Therefore, both improvement in visibility and reduction in moire fringes can be achieved.

Furthermore, it is preferable from the viewpoint of visibility that the antiglare layer does not substantially contain fine particles and a resin that is incompatible with the actinic radiation curable resin.

In the present application, “incompatible” means that when a melting temperature Tm or a glass transition point Tg of a molten mixture of two or more kinds of resins is measured and observed, each of the resins constituting the molten mixture has a single peak. What is observed. Further, it means that each phase is substantially observed in transmission electron microscope observation. On the other hand, “compatible” means that one or less of the peak of the molten mixture is observed when the melting temperature Tm or glass transition point Tg of the molten mixture of the same kind or two or more kinds of resins is measured and observed. .

In the present embodiment, the resin that is incompatible with the actinic radiation curable resin (details will be described later) is a resin obtained by polymerizing or copolymerizing (meth) acrylic or acrylic monomers. And polyester resins, and thermoplastic acrylic resins and cellulose ester resins used in the base film described later.

Examples of the fine particles include fine particles such as inorganic fine particles and organic fine particles, and specific examples of the inorganic fine particles include silicon oxide, magnesium oxide, and calcium carbonate. Further, as the organic particles, polymethacrylic acid methyl acrylate resin powder, acrylic styrene resin powder, polymethyl methacrylate resin powder, polystyrene resin powder, melamine resin powder, or the like can be added.

In the present application, “substantially does not contain” means that the content is less than the minimum amount affecting the compatibility when the melting temperature Tm or the glass transition point Tg is measured and observed. Say. The minimum amount varies depending on the type and properties of the particles and the incompatible resin.For example, in general, the content in the hard coat layer excludes the extract component from the film substrate, 0.01% by mass or less.

The antiglare layer according to the present embodiment mainly contains an actinic radiation curable resin, that is, a resin that cures through a crosslinking reaction by irradiation with actinic rays (also referred to as active energy rays) such as ultraviolet rays and electron beams. It is preferable to use a layer as a component.

As the actinic radiation curable resin, a component containing a monomer having an ethylenically unsaturated double bond is preferably used, and an actinic radiation curable resin layer is formed by curing by irradiation with actinic radiation such as ultraviolet rays or electron beams. The

Typical examples of the actinic radiation curable resin include ultraviolet curable resins and electron beam curable resins. However, resins cured by ultraviolet irradiation have excellent mechanical film strength (abrasion resistance, pencil hardness). To preferred.

Examples of the ultraviolet curable resin include an ultraviolet curable acrylate resin, an ultraviolet curable urethane acrylate resin, an ultraviolet curable polyester acrylate resin, an ultraviolet curable epoxy acrylate resin, an ultraviolet curable polyol acrylate resin, and an ultraviolet ray. A curable epoxy resin or the like is preferably used. Of these, ultraviolet curable acrylate resins are preferred.

As the ultraviolet curable acrylate resin, polyfunctional acrylate is preferable. The polyfunctional acrylate is preferably selected from the group consisting of pentaerythritol polyfunctional acrylate, dipentaerythritol polyfunctional acrylate, pentaerythritol polyfunctional methacrylate, and dipentaerythritol polyfunctional methacrylate. Here, the polyfunctional acrylate is a compound having two or more acryloyloxy groups or methacryloyloxy groups in the molecule. Examples of the polyfunctional acrylate monomer include ethylene glycol diacrylate, diethylene glycol diacrylate, 1,6-hexanediol diacrylate, neopentyl glycol diacrylate, trimethylolpropane triacrylate, trimethylolethane triacrylate, and tetramethylolmethane triacrylate. , Tetramethylolmethane tetraacrylate, pentaglycerol triacrylate, pentaerythritol diacrylate, pentaerythritol triacrylate, pentaerythritol tetraacrylate, pentaerythritol tri / tetraacrylate, ditrimethylolpropane tetraacrylate, ethoxylated pentaerythritol tetraacrylate, pentaerythritol tet Acrylate, glycerin triacrylate, dipentaerythritol triacrylate, dipentaerythritol tetraacrylate, dipentaerythritol pentaacrylate, dipentaerythritol hexaacrylate, tris (acryloyloxyethyl) isocyanurate, ethylene glycol dimethacrylate, diethylene glycol dimethacrylate, 1, 6-hexanediol dimethacrylate, neopentyl glycol dimethacrylate, trimethylolpropane trimethacrylate, trimethylolethane trimethacrylate, tetramethylolmethane trimethacrylate, tetramethylolmethane tetramethacrylate, pentaglycerol trimethacrylate, pentaerythritol dimethacrylate, pen Preferred examples include erythritol trimethacrylate, pentaerythritol tetramethacrylate, glycerin trimethacrylate, dipentaerythritol trimethacrylate, dipentaerythritol tetramethacrylate, dipentaerythritol pentamethacrylate, dipentaerythritol hexamethacrylate, active energy ray-curable isocyanurate derivatives, etc. It is done. The active energy ray-curable isocyanurate derivative is not particularly limited as long as it is a compound having a structure in which one or more ethylenically unsaturated groups are bonded to the isocyanuric acid skeleton. Compounds having an ethylenically unsaturated group and one or more isocyanurate rings are preferred.

As these commercial products, Adekaoptomer N series, Sunrad H-601, RC-750, RC-700, RC-600, RC-500, RC-611, RC-612 (manufactured by Sanyo Chemical Industries, Ltd.) SP-1509, SP-1507, Aronix M-6100, M-8030, M-8060, Aronix M-215, Aronix M-315, Aronix M-313, Aronix M-327 (manufactured by Toagosei Co., Ltd.), NK-ester A-TMM-3L, NK-ester AD-TMP, NK-ester ATM-35E, NK ester A-DOG, NK ester A-IBD-2E, A-9300, A-9300-1CL (Shin Nakamura Chemical) Kogyo Co., Ltd.), light acrylate TMP-A, PE-3A (Kyoeisha Chemical), and the like.

In addition, monofunctional acrylate may be used. Monofunctional acrylates include isobornyl acrylate, 2-hydroxy-3-phenoxypropyl acrylate, isostearyl acrylate, benzyl acrylate, ethyl carbitol acrylate, phenoxyethyl acrylate, lauryl acrylate, isooctyl acrylate, tetrahydrofurfuryl acrylate, behenyl Examples thereof include acrylate, 4-hydroxybutyl acrylate, 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, and cyclohexyl acrylate. Such monofunctional acrylates can be obtained from Nippon Kasei Kogyo Co., Ltd., Shin-Nakamura Chemical Co., Ltd., Osaka Organic Chemical Co., Ltd., etc.

In the case of using a monofunctional acrylate, it is preferable to contain polyfunctional acrylate: monofunctional acrylate = 70: 30 to 99: 2 in terms of mass ratio of polyfunctional acrylate and monofunctional acrylate. Actinic radiation curable resins may be used alone or in combination of two or more. The viscosity of the actinic radiation curable resin at 25 ° C. is preferably 20 mPa · s or more and 3000 mPa · s or less, more preferably 20 mPa · s or more and 2000 mPa · s or less. By using such a low-viscosity actinic ray curable resin, the above-described protrusion shape and arithmetic average roughness Ra are easily obtained. In addition, if the viscosity of the actinic radiation curable resin is 20 mPa · s or higher, a monomer having a high functionality can be used, and sufficiently high curability is obtained. If the viscosity is 3000 mPa · s or lower, the drying step In this case, it is easy to obtain sufficient fluidity of the actinic radiation curable resin.

In addition, the said viscosity is the value measured on 25 degreeC conditions using the B-type viscosity meter.

The antiglare layer preferably contains a photopolymerization initiator in order to accelerate the curing of the actinic radiation curable resin. The amount of the photopolymerization initiator is preferably contained in a mass ratio of photopolymerization initiator: active ray curable resin = 20: 100 to 0.01: 100. Specific examples of the photopolymerization initiator include alkylphenone series, acetophenone, benzophenone, hydroxybenzophenone, Michler ketone, α-amyloxime ester, thioxanthone, and derivatives thereof. In particular, it is not limited to these. A commercial item may be used for such a photoinitiator, for example, Irgacure 184, Irgacure 907, Irgacure 651, etc. by BASF Japan Ltd. are mentioned as a preferable illustration.

The antiglare layer may contain a conductive agent in order to impart antistatic properties. Preferable examples of the conductive agent include π-conjugated conductive polymers and ionic liquids.

The antiglare layer may contain a silicone surfactant, a fluorine surfactant, an acrylic surfactant, a fluorine-siloxane graft compound, or a compound having an HLB value of 3 to 18 from the viewpoint of coatability. good. A compound having an HLB value of 3 to 18 will be described. The HLB value is Hydrophile-Lipophile-Balance, hydrophilic-lipophilic-balance, and is a value indicating the hydrophilicity or lipophilicity of a compound. The smaller the HLB value, the higher the lipophilicity, and the higher the value, the higher the hydrophilicity. The HLB value can be obtained by the following calculation formula.
HLB = 7 + 11.7Log (Mw / Mo)

In the formula, Mw represents the molecular weight of the hydrophilic group, Mo represents the molecular weight of the lipophilic group, and Mw + Mo = M (molecular weight of the compound). Alternatively, according to the Griffin method, HLB value = 20 × total formula weight of hydrophilic part / molecular weight (J. Soc. Cosmetic Chem., 5 (1954), 294) and the like. Specific examples of the compound having an HLB value of 3 to 18 are listed below, but are not limited thereto. Figures in parentheses indicate HLB values.

Made by Kao Corporation: Emulgen 102KG (6.3), Emulgen 103 (8.1), Emulgen 104P (9.6), Emulgen 105 (9.7), Emulgen 106 (10.5), Emulgen 108 (12. 1), Emulgen 109P (13.6), Emulgen 120 (15.3), Emulgen 123P (16.9), Emulgen 147 (16.3), Emulgen 210P (10.7), Emulgen 220 (14.2) , Emulgen 306P (9.4), Emulgen 320P (13.9), Emulgen 404 (8.8), Emulgen 408 (10.0), Emulgen 409PV (12.0), Emulgen 420 (13.6), Emulgen 430 (16.2), Emulgen 705 (10.5), Emulgen 707 (12.1), Emulgen 09 (13.3), Emulgen 1108 (13.5), Emulgen 1118S-70 (16.4), Emulgen 1135S-70 (17.9), Emulgen 2020G-HA (13.0), Emulgen 2025G (15. 7), Emulgen LS-106 (12.5), Emulgen LS-110 (13.4), Emulgen LS-114 (14.0), manufactured by Nissin Chemical Industry Co., Ltd .: Surfynol 104E (4), Surfynol 104H (4), Surfinol 104A (4), Surfinol 104BC (4), Surfinol 104DPM (4), Surfinol 104PA (4), Surfinol 104PG-50 (4), Surfinol 104S (4), Surfy Knoll 420 (4), Surfynol 440 (8), Surfynol 4 5 (13), Surfynol 485 (17), Surfynol SE (6), manufactured by Shin-Etsu Chemical Co., Ltd .: X-22-4272 (7), X-22-6266 (8), KF-351 (12) KF-352 (7), KF-353 (10), KF-354L (16), KF-355A (12), KF-615A (10), KF-945 (4), KF-618 (11), KF-6011 (12), KF-6015 (4), KF-6004 (5).

Examples of the silicone surfactant include polyether-modified silicone, and the KF series manufactured by Shin-Etsu Chemical Co., Ltd. can be used. Examples of the acrylic surfactant include commercially available compounds such as BYK-350 and BYK-352 manufactured by BYK Japan. Examples of the fluorosurfactant include Megafac RS series, Megafac F-444 and Megafac F-556 manufactured by DIC Corporation. The fluorine-siloxane graft compound refers to a copolymer compound obtained by grafting polysiloxane and / or organopolysiloxane containing siloxane and / or organosiloxane alone to at least a fluorine-based resin. Examples of commercially available products include ZX-022H, ZX-007C, ZX-049, ZX-047-D manufactured by Fuji Kasei Kogyo Co., Ltd. These components are preferably added in a range of 0.01 to 3% by mass with respect to the solid component in the coating solution. The antiglare layer is prepared by diluting the above-described components for forming the antiglare layer with a solvent as an antiglare layer coating composition, and applying, drying and curing the antiglare layer coating composition on the film substrate in the following manner. Thus, it is preferable to provide an antiglare layer. Solvents include ketones (methyl ethyl ketone, acetone, cyclohexanone, methyl isobutyl ketone, etc.), esters (methyl acetate, ethyl acetate, butyl acetate, propyl acetate, propylene glycol monomethyl ether acetate, etc.), alcohols (ethanol, methanol, butanol, etc.) , N-propyl alcohol, isopropyl alcohol, diacetone alcohol), hydrocarbons (toluene, xylene, benzene, cyclohexane), glycol ethers (propylene glycol monomethyl ether, propylene glycol monopropyl ether, ethylene glycol monopropyl ether, etc.), etc. Can be preferably used. Further, among these solvents, glycol ethers or alcohols are used in the range of 20 to 200 parts by mass with respect to 100 parts by mass of the actinic radiation curable resin, so that the antiglare layer coating composition is applied to the base film. In the process of forming the antiglare layer while the solvent of the antiglare layer coating composition evaporates, convection of the resin is likely to occur, and as a result, irregular surface roughness is likely to occur in the antiglare layer. It is preferable because the arithmetic average roughness Ra can be easily controlled.

The coating amount of the antiglare layer is suitably 0.1 to 40 μm as a wet film thickness, and preferably 0.5 to 30 μm. The dry film thickness is from 0.1 to 30 μm, preferably from 1 to 20 μm, particularly preferably from 2 to 15 μm.

As a method for applying the antiglare layer, known methods such as a gravure coater, a dip coater, a reverse coater, a wire bar coater, a die coater, and an ink jet method can be used. Using these coating methods, an antiglare layer coating composition for forming an antiglare layer is applied, dried after application, irradiated with actinic radiation (also referred to as UV curing treatment), and, if necessary, after UV curing It can be formed by heat treatment. The heat treatment temperature after UV curing is preferably 80 ° C. or higher, more preferably 100 ° C. or higher, and particularly preferably 120 ° C. or higher. By performing the heat treatment after UV curing at such a high temperature, an antiglare layer having excellent pencil hardness can be obtained.

Drying is preferably performed by high-temperature treatment at a temperature of 90 ° C. or higher in the rate of drying section. More preferably, the temperature of the decreasing rate drying section is 90 ° C or higher and 160 ° C or lower. By setting the temperature of the reduced rate drying section to a high temperature treatment, convection of the coating film resin is likely to occur during the formation of the antiglare layer, and as a result, irregular surface roughness is likely to appear on the antiglare layer surface, This is preferable because the arithmetic average roughness Ra can be easily controlled.

In general, it is known that the drying process changes from a constant state to a gradually decreasing state when drying starts. The decreasing section is called the decreasing rate drying section. In the constant rate drying section, the amount of heat flowing in is all consumed for solvent evaporation on the coating film surface, and when the solvent on the coating film surface decreases, the evaporation surface moves from the surface to the inside and enters the decreasing rate drying section. After this, the temperature of the coating film surface rises and approaches the hot air temperature, and the temperature of the actinic radiation curable resin of the coating film rises. Thereby, it is thought that the convection of the coating film resin is caused by the decrease in the viscosity of the actinic radiation curable resin and the increase in fluidity.

As a light source for UV curing treatment, any light source that generates ultraviolet rays can be used without limitation. For example, a low pressure mercury lamp, a medium pressure mercury lamp, a high pressure mercury lamp, an ultrahigh pressure mercury lamp, a carbon arc lamp, a metal halide lamp, a xenon lamp, or the like can be used.

Irradiation conditions vary depending on each lamp, but the irradiation amount of active rays is usually 50 to 1000 mJ / cm ² , preferably 50 to 300 mJ / cm ² .

When irradiating actinic rays, it is preferably performed while applying tension in the transport direction of the film, more preferably while applying tension in the width direction. The tension to be applied is preferably 30 to 300 N / m. The method for applying tension is not particularly limited, and tension may be applied in the conveying direction on the back roll, or tension may be applied in the width direction or biaxial direction by a tenter. Thereby, a film having further excellent flatness can be obtained.

Further, the antiglare layer may further contain an ultraviolet absorber described in the base film described later. As a structure of the film in the case of containing an ultraviolet absorber, the antiglare layer is preferably composed of two or more layers, and the antiglare layer in contact with the base film preferably contains the ultraviolet absorber.

As the content of the ultraviolet absorber, it is preferable that it is contained in a mass ratio of ultraviolet absorber: antiglare layer constituting resin = 0.01: 100 to 10: 100. When two or more layers are provided, the film thickness of the antiglare layer in contact with the base film is preferably in the range of 0.05 to 2 μm. Two or more layers may be formed as a simultaneous multilayer. The simultaneous multi-layering means that two or more antiglare layers are applied on a wet substrate on a substrate without passing through a drying step to form an antiglare layer. In order to laminate the second anti-glare layer on the first anti-glare layer without using a drying process, the layers are stacked one after another with an extrusion coater or simultaneously with a slot die having a plurality of slits. Can be done.

In addition, the antiglare film according to the present embodiment has a pencil hardness, which is an index of hardness, of H or higher, more preferably 3H or higher. If it is 3H or more, it is not only difficult to be scratched in the polarizing plate forming step of the liquid crystal display device, but also used for outdoor applications, and is a surface protective film for large liquid crystal display devices and liquid crystal display devices for digital signage. Excellent mechanical properties when used. The pencil hardness is determined by JIS K5400 using a test pencil specified by JIS S 6006 under the condition of a weight of 500 g after conditioning the prepared antiglare film at a temperature of 23 ° C. and a relative humidity of 55% for 2 hours or more. It is a value measured according to the pencil hardness evaluation method specified. Next, the base film will be described.

<Base film>
It is preferable that the base film is easy to manufacture, easily adheres to the antiglare layer, and is optically isotropic. Moreover, in this embodiment, a base film is used as a polarizing plate protective film.

Any base film having the above properties may be used. For example, cellulose ester-based films such as triacetyl cellulose film, cellulose acetate propionate film, cellulose diacetate film, and cellulose acetate butyrate film, polyethylene terephthalate, polyethylene Polyester film such as naphthalate, polycarbonate film, polyarylate film, polysulfone (including polyethersulfone) film, polyethylene film, polypropylene film, cellophane, polyvinylidene chloride film, polyvinyl alcohol film, ethylene vinyl alcohol film, Syndiotactic polystyrene film, norbornene resin film, polymethylpente Films, polyether ketone films, polyether ketone imide film, a polyamide film, a fluorine resin film, nylon film, can be used cycloolefin polymer film, a polymethylmethacrylate film, or an acrylic film. Among these, cellulose ester films (for example, Konica Minoltac KC8UX, KC4UX, KC5UX, KC8UCR3, KC8UCR4, KC8UCR5, KC8UY, KC4UE, KC4UE, and KC12UR (above, manufactured by Konica Minolta Opto, Polycarbonate Co., Ltd.) An olefin polymer film and a polyester film are preferable, and in the present embodiment, the cellulose ester film is preferable from the viewpoint of ease of obtaining the above-described protruding shape with an antiglare layer, productivity, and cost. The refractive index of the base film is preferably 1.30 to 1.70, and more preferably 1.40 to 1.65. The refractive index is measured by the method of JIS K7142 using an upe refractometer 2T manufactured by Atago Co., Ltd.

Next, a cellulose ester film preferable as a base film will be described in more detail.

(Cellulose ester film)
The cellulose ester film is not particularly limited as long as it has the characteristics as the base film, but the cellulose ester resin (hereinafter also referred to as cellulose ester) is preferably a lower fatty acid ester of cellulose. The lower fatty acid in the lower fatty acid ester of cellulose means a fatty acid having 6 or less carbon atoms. For example, cellulose acetate, cellulose diacetate, cellulose triacetate, cellulose propionate, cellulose butyrate, cellulose acetate propionate, etc. Further, mixed fatty acid esters such as cellulose acetate butyrate can be used.

Among the above descriptions, the lower fatty acid esters of cellulose particularly preferably used are cellulose diacetate, cellulose triacetate, and cellulose acetate propionate. These cellulose esters can be used alone or in combination.

Cellulose diacetate preferably has an average degree of acetylation (amount of bound acetic acid) of 51.0 to 56.0%. Commercially available products include Daicel L20, L30, L40, and L50, and Eastman Chemical's Ca398-3, Ca398-6, Ca398-10, Ca398-30, and Ca394-60S.

The cellulose triacetate preferably has an average degree of acetylation (bound acetic acid amount) of 54.0 to 62.5%, and more preferably cellulose triacetate having an average degree of acetylation of 58.0 to 62.5%. is there.

If the average degree of acetylation is small, the dimensional change is large, and the polarization degree of the polarizing plate decreases. When the average degree of acetylation is large, the solubility in a solvent is lowered and the productivity is lowered.

The cellulose triacetate has an acetyl group substitution degree of 2.80 to 2.95, a number average molecular weight (Mn) of 125,000 or more and less than 155000, a weight average molecular weight (Mw) of 265,000 or more and less than 310,000, and Mw / Mn of Cellulose triacetate A of 1.9 to 2.1, acetyl group substitution degree of 2.75 to 2.90, number average molecular weight (Mn) of 155,000 to less than 180,000, Mw of 290000 to less than 360,000, Mw / Mn Preferably contains cellulose triacetate B which is 1.8 to 2.0. Further, when cellulose triacetate A and cellulose triacetate B are used in combination, the mass ratio is preferably in the range of cellulose triacetate A: cellulose triacetate B = 100: 0 to 20:80. A preferred cellulose ester other than cellulose triacetate has an acyl group having 2 to 4 carbon atoms as a substituent, the substitution degree of acetyl group is X, and the substitution degree of propionyl group or butyryl group is Y, It is a cellulose ester containing the cellulose ester which satisfy | fills (I) and (II) simultaneously.
Formula (I) 2.6 ≦ X + Y ≦ 3.0
Formula (II) 0 ≦ X ≦ 2.5

In particular, cellulose acetate propionate is preferably used, and among them, 1.9 ≦ X ≦ 2.5 and 0.1 ≦ Y ≦ 0.9 are preferable.

The number average molecular weight (Mn) and molecular weight distribution (Mw) of cellulose ester can be measured using high performance liquid chromatography. The measurement conditions are as follows.

Solvent: Methylene chloride Column: Shodex K806, K805, K803G
(Used by connecting three Showa Denko Co., Ltd.)
Column temperature: 25 ° C
Sample concentration: 0.1% by mass
Detector: RI Model 504 (GL Science Co., Ltd.)
Pump: L6000 (manufactured by Hitachi, Ltd.)
Flow rate: 1.0 ml / min
Calibration curve: Standard polystyrene STK standard polystyrene (manufactured by Tosoh Co., Ltd.) Mw = 1000,000 to 500 calibration curves with 13 samples were used. The 13 samples are preferably used at approximately equal intervals.

(Cellulose ester resin / thermoplastic acrylic resin-containing film)
The base film contains a thermoplastic acrylic resin and a cellulose ester resin, and the mass ratio of the thermoplastic acrylic resin to the cellulose ester resin is thermoplastic acrylic resin: cellulose ester resin = 95: 5 to 50:50. A certain film may be used.

Acrylic resin includes methacrylic resin. The acrylic resin is not particularly limited but is preferably composed of 50 to 99% by mass of methyl methacrylate units and 1 to 50% by mass of other monomer units copolymerizable therewith. Examples of other copolymerizable monomers include alkyl methacrylates having 2 to 18 alkyl carbon atoms, alkyl acrylates having 1 to 18 carbon atoms, alkyl acrylates such as acrylic acid and methacrylic acid. Unsaturated group-containing divalent carboxylic acids such as saturated acid, maleic acid, fumaric acid and itaconic acid, aromatic vinyl compounds such as styrene and α-methylstyrene, α, β-unsaturated nitriles such as acrylonitrile and methacrylonitrile, Examples thereof include maleic anhydride, maleimide, N-substituted maleimide, glutaric anhydride, and the like. These can be used alone or in combination of two or more monomers.

Among these, methyl acrylate, ethyl acrylate, n-propyl acrylate, n-butyl acrylate, s-butyl acrylate, 2-ethylhexyl acrylate, and the like are preferable from the viewpoint of thermal decomposition resistance and fluidity of the copolymer. n-Butyl acrylate is particularly preferably used. Further, the weight average molecular weight (Mw) is preferably 80,000 to 500,000, and more preferably 110,000 to 500,000.

The weight average molecular weight of the acrylic resin can be measured by gel permeation chromatography including the measurement conditions. There is no restriction | limiting in particular as a manufacturing method of an acrylic resin, You may use any well-known methods, such as suspension polymerization, emulsion polymerization, block polymerization, or solution polymerization. Here, as a polymerization initiator, a normal peroxide type and an azo type can be used, and a redox type can also be used. The polymerization temperature may be 30 to 100 ° C. for suspension or emulsion polymerization, and 80 to 160 ° C. for bulk or solution polymerization. In order to control the reduced viscosity of the obtained copolymer, polymerization can be carried out using alkyl mercaptan or the like as a chain transfer agent. Commercial products can also be used. For example, Delpet 60N, 80N (Asahi Kasei Chemicals Co., Ltd.), Dianal BR52, BR80, BR83, BR85, BR88 (Mitsubishi Rayon Co., Ltd.), KT75 (Electrochemical Industry Co., Ltd.) and the like can be mentioned. . Two or more acrylic resins can be used in combination. The acrylic resin may be a graft copolymer obtained by grafting a (meth) acrylic resin to a copolymer of (meth) acrylic rubber and an aromatic vinyl compound. In the graft copolymer, a copolymer of (meth) acrylic rubber and an aromatic vinyl compound forms a core, and the (meth) acrylic resin forms a shell around the copolymer. -A shell-type graft copolymer is preferred.

The total mass of the acrylic resin and the cellulose ester resin in the base film is preferably 55% by mass or more of the base film, more preferably 60% by mass or more, and particularly preferably 70% by mass or more. The base film may be configured to contain resins and additives other than thermoplastic acrylic resins and cellulose ester resins.

(Acrylic particles)
The base film may contain acrylic particles because it is excellent in improving brittleness. An acrylic particle represents the acrylic component which exists in the state of particle | grains (it is also called an incompatible state) in the base film which contains the said thermoplastic acrylic resin and cellulose-ester resin in a compatible state.

The acrylic particles are not particularly limited, but are preferably multi-layered acrylic granular composites. Examples of commercially available acrylic granular composites that are multi-layer structured polymers include, for example, “Metablene” manufactured by Mitsubishi Rayon Co., “Kaneace” manufactured by Kaneka Chemical Co., Ltd., “Paralloid” manufactured by Kureha Chemical Co., Ltd., Rohm and Examples include “Acryloid” manufactured by Haas, “Staffyroid” manufactured by Gantz Kasei Kogyo, and “Parapet SA” manufactured by Kuraray, and these may be used alone or in combination of two or more. When adding acrylic particles to the base film, it is preferable that the refractive index of the mixture of the acrylic resin and the cellulose ester resin is close to the refractive index of the acrylic particles in order to obtain a highly transparent film. Specifically, the refractive index difference between the acrylic particles and the acrylic resin is preferably 0.05 or less, more preferably 0.02 or less, and particularly preferably 0.01 or less.

Acrylic fine particles are in a range of 0.5: 100 to 30: 100 in terms of the content of acrylic fine particles: acrylic resin and cellulose ester resin with respect to the total mass of acrylic resin and cellulose ester resin constituting the film. The content is preferably from the viewpoint that the intended effect is better exhibited, and more preferably, the total mass of acrylic fine particles: acrylic resin and cellulose ester resin = 1.0: 100 to 15: 100.

[Fine particles]
In order to improve the handling property, the base film is, for example, silicon dioxide, titanium dioxide, aluminum oxide, zirconium oxide, calcium carbonate, kaolin, talc, calcined calcium silicate, hydrated calcium silicate, aluminum silicate, magnesium silicate. It is preferable to contain inorganic fine particles such as calcium phosphate and a matting agent such as a crosslinked polymer. Among these, silicon dioxide is preferably used because it can reduce the haze of the film.

The primary average particle diameter of the fine particles is preferably 20 nm or less, more preferably 5 to 16 nm, and particularly preferably 5 to 12 nm.

(Other additives)
A plasticizer can also be used in combination with the base film in order to improve the fluidity and flexibility of the composition. Examples of the plasticizer include phthalate ester, fatty acid ester, trimellitic ester, phosphate ester, polyester, and epoxy. Of these, polyester and phthalate plasticizers are preferably used. Polyester plasticizers are superior in non-migration and extraction resistance compared to phthalate ester plasticizers such as dioctyl phthalate. It can be applied to a wide range of uses by selecting or using these plasticizers according to the use.

The polyester plasticizer is a reaction product of a monovalent or tetravalent carboxylic acid and a monovalent or hexavalent alcohol, and is mainly obtained by reacting a divalent carboxylic acid with a glycol. . Representative divalent carboxylic acids include glutaric acid, itaconic acid, adipic acid, phthalic acid, azelaic acid, sebacic acid and the like. The polyester plasticizer is preferably an aromatic terminal ester plasticizer. The aromatic terminal ester plasticizer is preferably an ester compound having a structure obtained by reacting phthalic acid, adipic acid, at least one benzene monocarboxylic acid and at least one alkylene glycol having 2 to 12 carbon atoms. As long as it has an adipic acid residue and a phthalic acid residue as the structure of such a compound, when an ester compound is produced, it may be reacted as an acid anhydride or esterified product of dicarboxylic acid.

Examples of the benzene monocarboxylic acid component include benzoic acid, para-tert-butylbenzoic acid, orthotoluic acid, metatoluic acid, p-toluic acid, dimethylbenzoic acid, ethylbenzoic acid, normal propylbenzoic acid, aminobenzoic acid, acetoxybenzoic acid and the like. Most preferred is benzoic acid. Moreover, these can each be used as a 1 type, or 2 or more types of mixture.

Examples of the alkylene glycol component having 2 to 12 carbon atoms include ethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, 1,2-butanediol, 1,3-butanediol, 1,2-propanediol, 2-methyl 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 2,2-dimethyl-1,3-propanediol (neopentyl glycol), 2,2-diethyl-1, 3-propanediol (3,3-dimethylolpentane), 2-n-butyl-2-ethyl-1,3-propanediol (3,3-dimethylolheptane), 3-methyl-1,5-pentanediol 1 , 6-hexanediol, 2,2,4-trimethyl 1,3-pentanediol, 2-ethyl 1,3-hexanediol 2-methyl-1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, 1,12-octadecane diol. Of these, 1,2-propylene glycol is particularly preferred. These glycols may be used as one kind or a mixture of two or more kinds.

The aromatic terminal ester plasticizer may be either an oligoester type or a polyester type, and the molecular weight is preferably in the range of 100 to 10,000, but is preferably in the range of 350 to 3000. The acid value is 1.5 mgKOH / g or less, the hydroxy group value (hydroxyl value) is 25 mgKOH / g or less, more preferably the acid value is 0.5 mgKOH / g or less, and the hydroxy group value (hydroxyl value) is 15 mgKOH / g or less. Is.

The plasticizer is preferably added in an amount of 0.5 to 30 parts by mass with respect to 100 parts by mass of the base film. Specific examples thereof include, but are not limited to, compounds (B-1 to B-10) shown below.

Furthermore, the base film may contain a sugar ester compound. The sugar ester compound is a compound obtained by esterifying all or part of the OH group of a sugar such as the following monosaccharide, disaccharide, trisaccharide or oligosaccharide. As a more specific example, a general formula (1) The compound etc. which are represented by these can be mention | raise | lifted.

(Wherein R ₁ to R ₈ represent a substituted or unsubstituted alkylcarbonyl group having 2 to 22 carbon atoms, or a substituted or unsubstituted arylcarbonyl group having 2 to 22 carbon atoms, and R ₁ to R ₈ May be the same or different.)

The compounds represented by the general formula (1) are shown below in more detail (compound 1-1 to compound 1-23), but are not limited thereto. In the table below, R represents any one of R ₁ to R ₈ . The “average degree of substitution” in the table below indicates the degree of substitution of R ₁ to R ₈ . For example, an average degree of substitution of 6.0 indicates that the number of R ₁ to R ₈ that are substituted with any of the following R is 6 on average. R ₁ to R ₈ in the compound represented by the general formula (1) are unsubstituted except for those substituted with R, that is, a hydrogen atom is bonded.

The base film preferably contains an ultraviolet absorber, and examples of the ultraviolet absorber used include benzotriazole, 2-hydroxybenzophenone, and salicylic acid phenyl ester. For example, 2- (5-methyl-2-hydroxyphenyl) benzotriazole, 2- [2-hydroxy-3,5-bis (α, α-dimethylbenzyl) phenyl] -2H-benzotriazole, 2- (3 Triazoles such as 5-di-t-butyl-2-hydroxyphenyl) benzotriazole, 2-hydroxy-4-methoxybenzophenone, 2-hydroxy-4-octoxybenzophenone, 2,2'-dihydroxy-4-methoxybenzophenone And benzophenones.

Among UV absorbers, UV absorbers with a molecular weight of 400 or more are difficult to volatilize at high boiling points and are difficult to disperse even during high temperature molding, so that the weather resistance can be effectively improved with a relatively small amount of addition. Can do.

Examples of the ultraviolet absorber having a molecular weight of 400 or more include 2- [2-hydroxy-3,5-bis (α, α-dimethylbenzyl) phenyl] -2-benzotriazole, 2,2-methylenebis [4- (1, 1,3,3-tetrabutyl) -6- (2H-benzotriazol-2-yl) phenol], bis (2,2,6,6-tetramethyl-4-piperidyl) sebacate, bis ( Hindered amines such as 1,2,2,6,6-pentamethyl-4-piperidyl) sebacate and 2- (3,5-di-t-butyl-4-hydroxybenzyl) -2-n-butylmalonic acid Bis (1,2,2,6,6-pentamethyl-4-piperidyl), 1- [2- [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionyloxy] Such as til] -4- [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionyloxy] -2,2,6,6-tetramethylpiperidine Examples include hybrid systems having both structures, and these can be used alone or in combination of two or more. Among these, 2- [2-hydroxy-3,5-bis (α, α-dimethylbenzyl) phenyl] -2-benzotriazole and 2,2-methylenebis [4- (1,1,3,3- Tetrabutyl) -6- (2H-benzotriazol-2-yl) phenol] is particularly preferred.

These may be commercially available products, and for example, TINUVIN such as TINUVIN 109, TINUVIN 171, TINUVIN 234, TINUVIN 326, TINUVIN 327, TINUVIN 328, and TINUVIN 928 manufactured by BASF Japan Ltd. can be preferably used. Furthermore, various antioxidants can also be added to the base film in order to improve the thermal decomposability and thermal colorability during molding. It is also possible to add an antistatic agent to give the base film antistatic performance.

For the base film, a flame retardant acrylic resin composition containing a phosphorus flame retardant may be used. Phosphorus flame retardants used here include red phosphorus, triaryl phosphate ester, diaryl phosphate ester, monoaryl phosphate ester, aryl phosphonate compound, aryl phosphine oxide compound, condensed aryl phosphate ester, halogenated alkyl phosphorus. Examples thereof include one or a mixture of two or more selected from acid esters, halogen-containing condensed phosphate esters, halogen-containing condensed phosphonate esters, halogen-containing phosphite esters, and the like.

Specific examples include triphenyl phosphate, 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, phenylphosphonic acid, tris (β-chloroethyl) phosphate, tris (dichloropropyl) Examples thereof include phosphate and tris (tribromoneopentyl) phosphate.

The base film is required to withstand use in a higher temperature environment, and if the tension softening point of the base film is 105 to 145 ° C., it can be judged that the base film exhibits sufficient heat resistance. 110 to 130 ° C. is particularly preferable.

As a specific method for measuring the tension softening point, for example, a Tensilon tester (ORIENTEC Co., RTC-1225A) is used to cut out the optical film at 120 mm (length) × 10 mm (width) and pull it with a tension of 10 N. However, the temperature can be continuously increased at a rate of temperature increase of 30 ° C./min, and the temperature at 9 N can be measured three times, and the average value can be obtained.

The glass transition temperature referred to here is an intermediate value determined according to JIS K7121 (1987) using a differential scanning calorimeter (DSC-7 model manufactured by Perkin Elmer) at a heating rate of 20 ° C./min. Point glass transition temperature (Tmg).

When a substrate film is used as a protective film for a polarizing plate of a liquid crystal display device, unevenness or a change in retardation value occurs due to a dimensional change due to moisture absorption, causing problems such as a decrease in contrast and uneven color. In particular, the above problem becomes significant when the polarizing plate protective film is used in a liquid crystal display device used outdoors. For this reason, the dimensional change rate (%) is preferably less than 0.5%, and more preferably less than 0.3%. The base film preferably has a defect of 5 μm or more in diameter in the film plane of 1 piece / 10 cm square or less. More preferably, it is 0.5 piece / 10 cm square or less, more preferably 0.1 piece / 10 cm square or less. Here, the diameter of the defect indicates the diameter when the defect is circular, and when the defect is not circular, the range of the defect is determined by observing with a microscope by the following method, and the maximum diameter (diameter of circumscribed circle) is determined.

The range of the defect is the size of the shadow when the defect is observed with the transmitted light of the differential interference microscope when the defect is a bubble or a foreign object. When the defect is a change in the surface shape, such as transfer of a roll flaw or an abrasion, the size is confirmed by observing the defect with the reflected light of a differential interference microscope.

In addition, when observing with reflected light, if the size of the defect is not clear, aluminum or platinum is vapor-deposited on the surface for observation. In order to obtain a film having excellent quality expressed by such a defect frequency with high productivity, it is necessary to filter the polymer solution with high precision immediately before casting, to increase the cleanliness around the casting machine, It is effective to set drying conditions after rolling stepwise and to dry efficiently while suppressing foaming.

When the number of defects is more than 1/10 cm square, for example, when a tension is applied to the film during processing in a later process, the film may be broken with the defect as a starting point and productivity may be reduced. Moreover, when the diameter of a defect becomes 5 micrometers or more, it can confirm visually by polarizing plate observation etc., and when used as an optical member, a bright spot may arise.

Also, even when visual confirmation is not possible, when a hard coat layer or the like is formed on the film, the coating agent may not be formed uniformly, resulting in defects (coating defects). Here, the defect is a void in the film (foaming defect) generated due to the rapid evaporation of the solvent in the drying process of the solution casting, a foreign substance in the film forming stock solution, or a foreign substance mixed in the film forming process. This refers to the foreign matter (foreign matter defect) in the film.

Further, the base film preferably has a breaking elongation in at least one direction of 10% or more, more preferably 20% or more in the measurement based on JIS-K7127-1999. The upper limit of the elongation at break is not particularly limited, but is practically about 250%. In order to increase the elongation at break, it is effective to suppress defects in the film caused by foreign matter and foaming. The thickness of the base film is preferably 10 μm or more. More preferably, it is 20 μm or more. The upper limit of the thickness is not particularly limited, but in the case of forming a film by a solution casting method, the upper limit is about 250 μm from the viewpoint of applicability, foaming, solvent drying, and the like. In addition, the thickness of a film can be suitably selected according to a use.

The base film preferably has a total light transmittance of 90% or more, more preferably 93% or more. Moreover, as a realistic upper limit, it is about 99%. In order to achieve excellent transparency expressed by such total light transmittance, it is necessary not to introduce additives and copolymerization components that absorb visible light, or to remove foreign substances in the polymer by high-precision filtration. It is effective to reduce the diffusion and absorption of light inside the film. Also, reduce the surface roughness of the film surface by reducing the surface roughness of the film contact part (cooling roll, calender roll, drum, belt, coating substrate in solution casting, transport roll, etc.) during film formation. It is also effective to reduce the diffusion and reflection of light on the film surface by reducing the refractive index of the acrylic resin.

(Formation of base film)
As a method for forming the base film, a production method such as an inflation method, a T-die method, a calendar method, a cutting method, a casting method, an emulsion method, a hot press method, or the like can be used.

From the viewpoint of suppressing the residual solvent using a cellulose ester resin or an acrylic resin for dissolution, a method of producing by a melt casting film forming method is preferable. Methods formed by melt casting can be classified into melt extrusion molding methods, press molding methods, inflation methods, injection molding methods, blow molding methods, stretch molding methods, and the like. Among these, the melt extrusion method is preferable, in which a film having excellent mechanical strength and surface accuracy can be obtained. From the viewpoints of suppressing coloring, suppressing defects of foreign matters, and suppressing optical defects such as die lines, solution casting by casting is preferred. Moreover, after the film-forming material is heated to exhibit its fluidity, a method of extrusion film formation on a drum or an endless belt is also included as a melt casting film formation method.

[Organic solvent]
The organic solvent useful for forming the dope when the base film is produced by the solution casting method can be used without limitation as long as it dissolves acrylic resin, cellulose ester resin, and other additives simultaneously. .

For example, as a chlorinated organic solvent, methylene chloride, as a non-chlorinated organic solvent, methyl acetate, ethyl acetate, amyl acetate, acetone, tetrahydrofuran, 1,3-dioxolane, 1,4-dioxane, cyclohexanone, ethyl formate, 2,2,2-trifluoroethanol, 2,2,3,3-hexafluoro-1-propanol, 1,3-difluoro-2-propanol, 1,1,1,3,3,3-hexafluoro- 2-methyl-2-propanol, 1,1,1,3,3,3-hexafluoro-2-propanol, 2,2,3,3,3-pentafluoro-1-propanol, nitroethane, etc. Methylene chloride, methyl acetate, ethyl acetate and acetone can be preferably used.

In addition to the organic solvent, the dope preferably contains 1 to 40% by mass of a linear or branched aliphatic alcohol having 1 to 4 carbon atoms. When the proportion of alcohol in the dope increases, the web gels and peeling from the metal support becomes easy, and when the proportion of alcohol is small, the acrylic resin and cellulose ester resin dissolve in a non-chlorine organic solvent system. There is also a role to promote. In particular, in a solvent containing methylene chloride and a linear or branched aliphatic alcohol having 1 to 4 carbon atoms, at least 15 to 45 mass% in total of at least three kinds of acrylic resin, cellulose ester resin, and acrylic particles are used. A dissolved dope composition is preferred. Examples of the linear or branched aliphatic alcohol having 1 to 4 carbon atoms include methanol, ethanol, n-propanol, iso-propanol, n-butanol, sec-butanol, and tert-butanol. Ethanol is preferred because of the stability of these dopes, the relatively low boiling point, and good drying properties.

[Solution casting method]
The base film can be produced by a solution casting method. In the solution casting method, a step of preparing a dope by dissolving a resin and an additive in a solvent, a step of casting the dope on a belt-like or drum-like metal support, and a step of drying the cast dope as a web , Peeling from the metal support, stretching or maintaining the width, further drying, and winding the finished film.

The concentration of cellulose ester in the dope, and the concentration of cellulose ester resin / acrylic resin is preferably higher because the drying load after casting on a metal support can be reduced. Will increase the filtration accuracy. The concentration that achieves both of these is preferably 10 to 35% by mass, and more preferably 15 to 25% by mass. The metal support in the casting (casting) step preferably has a mirror-finished surface, and a stainless steel belt or a drum whose surface is plated with a casting is preferably used as the metal support.

The cast width can be 1 ~ 4m. The surface temperature of the metal support in the casting step is set to −50 ° C. to below the temperature at which the solvent boils and does not foam. A higher temperature is preferred because the web can be dried faster, but if it is too high, the web may foam or the flatness may deteriorate.

A preferable support temperature is appropriately determined at 0 to 100 ° C., and more preferably 5 to 30 ° C. Alternatively, it is also a preferable method that the web is gelled by cooling and peeled from the drum in a state containing a large amount of residual solvent. The method for controlling the temperature of the metal support is not particularly limited, and there are a method of blowing warm air or cold air, and a method of contacting hot water with the back side of the metal support. It is preferable to use warm water because heat transfer is performed efficiently, so that the time until the temperature of the metal support becomes constant is short.

When using warm air, considering the temperature drop of the web due to the latent heat of vaporization of the solvent, while using warm air above the boiling point of the solvent, there may be cases where wind at a temperature higher than the target temperature is used while preventing foaming. .

In particular, it is preferable to perform drying efficiently by changing the temperature of the support and the temperature of the drying air during the period from casting to peeling.

In order for the cellulose ester film to exhibit good flatness, the amount of residual solvent when peeling the web from the metal support is preferably 10 to 150% by mass, more preferably 20 to 40% by mass or 60 to 130% by mass. Particularly preferred is 20 to 30% by mass or 70 to 120% by mass.

The amount of residual solvent is defined by the following formula.
Residual solvent amount (% by mass) = {(MN) / N} × 100

Note that M is the mass of a sample collected during or after the production of the web or film, and N is the mass after heating M at 115 ° C. for 1 hour.

Further, in the drying step of the cellulose ester film or the cellulose ester resin / acrylic resin film, it is preferable that the web is peeled off from the metal support and further dried to make the residual solvent amount 1% by mass or less, more preferably 0. 0.1 mass% or less, particularly preferably 0 to 0.01 mass% or less.

In the film drying process, generally, a roll drying method (a method in which webs are alternately passed through a plurality of rolls arranged above and below) and a method in which the web is dried while being conveyed by a tenter method are employed.

[Stretching process]
In the stretching step, the film can be sequentially or simultaneously stretched in the longitudinal direction (MD direction) and the width direction (TD direction) of the film. The draw ratios in the biaxial directions perpendicular to each other are preferably in the range of 1.0 to 2.0 times in the MD direction and 1.07 to 2.0 times in the TD direction, respectively. It is preferably performed in the range of 1.0 to 1.5 times and 1.07 to 2.0 times in the TD direction. For example, a method in which peripheral speed differences are applied to a plurality of rolls and a roll peripheral speed difference is used to stretch in the MD direction, both ends of the web are fixed with clips and pins, and the distance between the clips and pins is increased in the traveling direction. And a method of stretching in the MD direction, a method of stretching in the transverse direction and stretching in the TD direction, a method of stretching in the MD / TD direction simultaneously and stretching in both the MD / TD directions, and the like. These width maintenance or width direction stretching in the film forming step is preferably performed by a tenter, and may be a pin tenter or a clip tenter.

The film transport tension in the film forming process such as in the tenter depends on the temperature, but is preferably 120 to 200 N / m, more preferably 140 to 200 N / m. 140 to 160 N / m is most preferable.

When stretching, assuming that the glass transition temperature of the substrate film is Tg, (Tg-30) to (Tg + 100) ° C., more preferably (Tg-20) to (Tg + 80) ° C., and more preferably (Tg-5) to (T Tg + 20) ° C.

The Tg of the base film can be controlled by the type of material constituting the film and the ratio of the constituting materials. In the application of the present embodiment, the Tg when the film is dried is preferably 110 ° C. or higher, more preferably 120 ° C. or higher. Especially preferably, it is 150 degreeC or more.

Therefore, the glass transition temperature is preferably 190 ° C. or lower, more preferably 170 ° C. or lower. At this time, the Tg of the film can be determined by the method described in JIS K7121.

When the stretching temperature is 150 ° C. or more and the stretching ratio is 1.15 times or more, the surface is suitably roughened, which is preferable. Roughening the film surface is preferable because it improves not only the slipperiness but also the surface processability, particularly the adhesion of the antiglare layer.

[Melting method]
The base film may be formed by a melt film forming method. The melt film-forming method refers to heating and melting a composition containing an additive such as a resin and a plasticizer to a temperature exhibiting fluidity, and then casting a melt containing a fluid cellulose ester.

The molding method for heating and melting can be further classified into a melt extrusion molding method, a press molding method, an inflation method, an injection molding method, a blow molding method, a stretch molding method, and the like. Among these molding methods, the melt extrusion method is preferable from the viewpoint of mechanical strength and surface accuracy. It is preferable that a plurality of raw materials used for melt extrusion are usually kneaded in advance and pelletized.

Pelletization may be performed by a known method. For example, dry cellulose ester, plasticizer, and other additives are fed to an extruder using a feeder, kneaded using a single or twin screw extruder, and extruded from a die into a strand. It can be done by water cooling or air cooling and cutting.

Additives may be mixed before being supplied to the extruder, or may be supplied by individual feeders.

A small amount of additives such as particles and antioxidants are preferably mixed before mixing in order to mix uniformly.

The extruder is preferably processed at as low a temperature as possible so that it can be pelletized so as to suppress the shearing force and prevent the resin from deteriorating (molecular weight reduction, coloring, gel formation, etc.). For example, in the case of a twin screw extruder, it is preferable to rotate in the same direction using a deep groove type screw. From the uniformity of kneading, the meshing type is preferable.

Film formation is performed using the pellets obtained as described above. Of course, the raw material powder can be directly fed to the extruder by a feeder without being pelletized to form a film as it is.

Using a single-screw or twin-screw type extruder, the melting temperature when extruding is about 200-300 ° C, filtered through a leaf disk type filter, etc. to remove foreign matter, and then formed into a film from the T-die. The film is cast and the film is nipped by a cooling roll and an elastic touch roll, and solidified on the cooling roll.

When introducing into the extruder from the supply hopper, it is preferable to prevent oxidative decomposition or the like under vacuum, reduced pressure, or inert gas atmosphere.

The extrusion flow rate is preferably carried out stably by introducing a gear pump. Further, a stainless fiber sintered filter is preferably used as a filter used for removing foreign substances. The stainless steel fiber sintered filter is a united stainless steel fiber body that is intricately intertwined and compressed, and the contact points are sintered and integrated. The density of the fiber is changed depending on the thickness of the fiber and the amount of compression, and the filtration accuracy is improved. Can be adjusted.

Additives such as plasticizers and particles may be mixed with the resin in advance, or may be kneaded in the middle of the extruder. In order to add uniformly, it is preferable to use a mixing apparatus such as a static mixer.

The film temperature on the touch roll side when the film is nipped by the cooling roll and the elastic touch roll is preferably Tg or more and Tg + 110 ° C. or less of the film. A well-known roll can be used for the roll which has the elastic body surface used for such a purpose.

The elastic touch roll is also called a pinching rotator. As the elastic touch roll, a commercially available one can be used.

When peeling the film from the cooling roll, it is preferable to control the tension to prevent deformation of the film.

Moreover, it is preferable that the film obtained as described above is stretched by the stretching operation after passing through the step of contacting the cooling roll.

As the stretching method, a known roll stretching machine or tenter can be preferably used. The stretching temperature is usually preferably in the temperature range of Tg to Tg + 60 ° C. of the resin constituting the film.

Before winding, the end may be slit and cut to the product width, and knurled (embossed) may be applied to both ends to prevent sticking or scratching during winding. The knurling method can process a metal ring having an uneven pattern on its side surface by heating or pressing. In addition, since the film has deform | transformed and cannot use as a product normally, the holding | grip part of the clip of both ends of a film is cut out and reused.

(Physical properties of base film)
The film thickness of the substrate film in the present embodiment is not particularly limited, but 10 to 200 μm is used. In particular, the film thickness is particularly preferably 10 to 100 μm. More preferably, it is 20 to 60 μm.

The base film according to this embodiment has a width of 1 to 4 m. In particular, those having a width of 1.4 to 4 m are preferably used, and particularly preferably 1.6 to 3 m. If it exceeds 4 m, conveyance becomes difficult.

Further, the arithmetic average roughness Ra of the base film is preferably 2.0 to 4.0 nm, more preferably 2.5 to 3.5 nm.

<Functional layer>
The antiglare film according to the present embodiment can be provided with functional layers such as a backcoat layer and an antireflection layer.

(Back coat layer)
The anti-glare film according to the present embodiment is a back surface for preventing sticking when a curl or anti-glare film is stored in a roll on the surface opposite to the side on which the anti-glare layer of the base film is provided. A coat layer may be provided.

The back coat layer preferably contains fine particles for the above purpose, and the fine particles include silicon dioxide, titanium dioxide, aluminum oxide, zirconium oxide, calcium carbonate, calcium carbonate, talc, clay, calcined kaolin, calcined silicic acid. Mention may be made of calcium, tin oxide, indium oxide, zinc oxide, ITO, hydrated calcium silicate, aluminum silicate, magnesium silicate and calcium phosphate. Moreover, it is preferable to contain a solvent in order to disperse the fine particles and to dissolve a binder described later to form a coating composition. As the solvent, the solvents described in the antiglare layer are preferable. The particles contained in the back coat layer are preferably 0.1 to 50% by mass with respect to the binder. When the back coat layer is provided, the increase in haze is preferably 1.5% or less, and 0.5% or less. Further, it is preferable to use a cellulose ester resin such as diacetyl cellulose as the binder.

(Antireflection layer)
The antiglare film according to the present embodiment is provided with a low refractive index layer which is an antireflection layer directly or via another layer on the antiglare layer, so that the adhesion between the low refractive index layer and the antiglare layer is improved. In addition, it is preferable to use the antiglare film according to the present embodiment for the antiglare antireflection film from the viewpoint that the occurrence of spotted unevenness in the low refractive index layer can be satisfactorily suppressed and an excellent appearance can be obtained. The antireflection layer composed of the low refractive index layer may have a single layer configuration consisting of only the low refractive index layer, but may also be a multilayer. Specifically, a high refractive index layer having a higher refractive index than the support and a low refractive index layer having a lower refractive index than the support can be combined. Further, three layers having different refractive indexes from the support side are divided into a medium refractive index layer (a layer having a higher refractive index than the support or the antiglare layer and a lower refractive index than the high refractive index layer) / high refractive index layer / low. You may laminate | stack in order of a refractive index layer. Further, an antireflection layer having a layer structure of four or more layers in which two or more high refractive index layers and two or more low refractive index layers are alternately laminated is also preferably used. An example of a preferable layer configuration of the antireflection layer is shown below. Here, / indicates that the layers are arranged in layers.

Base film / Anti-glare layer / Low refractive index layer Base film / Anti-glare layer / High refractive index layer / Low refractive index layer Base film / Anti-glare layer / Medium refractive index layer / High refractive index layer / Low refractive index Layer An antifouling layer may be further provided on the outermost low refractive index layer so that dirt and fingerprints can be easily wiped off. As the antifouling layer, fluorine-containing organic compounds are preferably used.

As long as the reflectance can be reduced by optical interference, it is not limited to these layer configurations. In the above layer structure, an intermediate layer may be provided as appropriate. For example, an antistatic layer containing conductive polymer fine particles (for example, crosslinked cation fine particles) or metal oxide fine particles (for example, SnO ₂ , ITO) is preferable.

<Low refractive index layer>
In the low refractive index layer, a layer lower than the refractive index of the base film is formed, and the refractive index is preferably in the range of 1.30 to 1.45 when measured at 23 ° C. and wavelength of 550 nm.

The thickness of the low refractive index layer is not particularly limited, but is preferably 5 nm to 0.5 μm, more preferably 10 nm to 0.3 μm, and more preferably 30 nm to 0.2 μm. Most preferred. The low refractive index layer preferably uses hollow spherical silica-based fine particles from the viewpoint of refractive index adjustment and mechanical strength.

(Hollow spherical silica-based fine particles)
The hollow spherical fine particles are (I) composite particles comprising porous particles and a coating layer provided on the surface of the porous particles, or (II) having a cavity inside, and the content is a solvent, gas or porous Cavity particles filled with a substance. Note that the low refractive index layer only needs to contain either (I) composite particles or (II) hollow particles, or both.

Note that the cavity particles are particles having a cavity inside, and the cavity is surrounded by a particle wall. The cavity is filled with contents such as a solvent, a gas, or a porous material used at the time of preparation. It is desirable that the average particle size of such hollow spherical fine particles is in the range of 5 to 300 nm, preferably 10 to 200 nm. The hollow spherical fine particles used are appropriately selected according to the thickness of the transparent film to be formed, and are in the range of 2/3 to 1/10 of the film thickness of the transparent film such as the low refractive index layer to be formed. Is desirable. These hollow spherical fine particles are preferably used in a state of being dispersed in an appropriate medium in order to form a low refractive index layer. As the dispersion medium, water, alcohol (for example, methanol, ethanol, isopropyl alcohol), ketone (for example, methyl ethyl ketone, methyl isobutyl ketone), and ketone alcohol (for example, diacetone alcohol) are preferable.

The thickness of the coating layer of the composite particles or the thickness of the particle walls of the hollow particles is desirably 1 to 20 nm, preferably 2 to 15 nm. In the case of composite particles, if the thickness of the coating layer is less than 1 nm, the particles may not be completely covered, and it is easy to use a silicate monomer or oligomer having a low polymerization degree, which is a coating liquid component described later. The inside of the composite particles may enter and the internal porosity may decrease, and the low refractive index effect may not be sufficiently obtained. When the thickness of the coating layer exceeds 20 nm, the silicic acid monomer and oligomer do not enter the inside, but the porosity (pore volume) of the composite particles is lowered and the effect of low refractive index is sufficiently obtained. It may not be possible. In the case of hollow particles, if the particle wall thickness is less than 1 nm, the particle shape may not be maintained, and even if the thickness exceeds 20 nm, the effect of low refractive index may not be sufficiently exhibited. is there.

The coating layer of the composite particles or the particle wall of the hollow particles is preferably composed mainly of silica. Moreover, components other than silica may be contained, and specifically, Al ₂ O ₃ , B ₂ O ₃ , TiO ₂ , ZrO ₂ , SnO ₂ , CeO ₂ , P ₂ O ₃ , Sb ₂ O _3. , MoO ₃ , ZnO ₂ , WO _{3 and the} like. Examples of the porous particles constituting the composite particles include those made of silica, those made of silica and an inorganic compound other than silica, and those made of CaF ₂ , NaF, NaAlF ₆ , MgF, and the like. Among these, porous particles made of a composite oxide of silica and an inorganic compound other than silica are particularly preferable. Examples of inorganic compounds other than silica include Al ₂ O ₃ , B ₂ O ₃ , TiO ₂ , ZrO ₂ , SnO ₂ , CeO ₂ , P ₂ O ₃ , Sb ₂ O ₃ , MoO ₃ , ZnO ₂ and WO _3. 1 type or 2 types or more can be mentioned. In such porous particles, the molar ratio MOX / SiO ₂ when the silica is represented by SiO ₂ and the inorganic compound other than silica is represented by oxide (MOX) is 0.0001 to 1.0, preferably It is desirable to be in the range of 0.001 to 0.3. It is difficult to obtain a porous particle having a molar ratio MOX / SiO ₂ of less than 0.0001. Even if it is obtained, particles having a small pore volume and a low refractive index cannot be obtained. Further, when the molar ratio MOX / SiO _{2 of} the porous particles exceeds 1.0, the ratio of silica decreases, so that the pore volume increases and it may be difficult to obtain a material having a lower refractive index. . The pore volume of such porous particles is desirably in the range of 0.1 to 1.5 ml / g, preferably 0.2 to 1.5 ml / g. If the pore volume is less than 0.1 ml / g, particles having a sufficiently reduced refractive index cannot be obtained. If the pore volume exceeds 1.5 ml / g, the strength of the fine particles is lowered, and the strength of the resulting coating may be lowered. is there. In addition, the pore volume of such porous particles can be determined by a mercury intrusion method. Such hollow spherical fine particles can be produced from the following first to third steps.

First Step: Preparation of Porous Particle Precursor In the first step, an alkali aqueous solution of a silica raw material and an inorganic compound raw material other than silica is separately prepared in advance, or a silica raw material and an inorganic compound raw material other than silica are prepared in advance. A mixed aqueous solution is prepared, and this aqueous solution is gradually added to an aqueous alkaline solution having a pH of 10 or more while stirring according to the composite ratio of the target composite oxide to prepare a porous particle precursor.

As the silica raw material, alkali metal, ammonium or organic base silicate is used. Sodium silicate (water glass) or potassium silicate is used as the alkali metal silicate. Examples of the organic base include quaternary ammonium salts such as tetraethylammonium salt, and amines such as monoethanolamine, diethanolamine, and triethanolamine. The ammonium silicate or organic base silicate includes an alkaline solution obtained by adding ammonia, a quaternary ammonium hydroxide, an amine compound, or the like to a silicate solution.

In addition, alkali-soluble inorganic compounds are used as raw materials for inorganic compounds other than silica. Specifically, an oxo acid of an element selected from Al, B, Ti, Zr, Sn, Ce, P, Sb, Mo, Zn, W, etc., an alkali metal salt or alkaline earth metal salt of the oxo acid, ammonium And salts and quaternary ammonium salts. More specifically, sodium aluminate, sodium tetraborate, zirconyl ammonium carbonate, potassium antimonate, potassium stannate, sodium aluminosilicate, sodium molybdate, cerium ammonium nitrate, and sodium phosphate are suitable.

Although the pH value of the mixed aqueous solution changes simultaneously with the addition of these aqueous solutions, an operation for controlling the pH value within a predetermined range is not particularly required. The aqueous solution finally has a pH value determined by the type of inorganic oxide and the mixing ratio thereof. There is no restriction | limiting in particular in the addition rate of the aqueous solution at this time. Further, in the production of composite oxide particles, a dispersion of seed particles can be used as a starting material. The seed particles are not particularly limited, but inorganic oxides such as SiO ₂ , Al ₂ O ₃ , TiO ₂ or ZrO ₂ or fine particles of these composite oxides are used. Usually, these sols are used. Can do. Furthermore, the porous particle precursor dispersion obtained by the above production method may be used as a seed particle dispersion. When using a seed particle dispersion, the pH of the seed particle dispersion is adjusted to 10 or higher, and then an aqueous solution of the compound is added to the above-mentioned alkaline aqueous solution while stirring. Also in this case, it is not always necessary to control the pH of the dispersion. When seed particles are used in this way, it is easy to control the particle size of the porous particles to be prepared, and particles with uniform particle sizes can be obtained.

The silica raw material and inorganic compound raw material described above have high solubility on the alkali side. However, when both are mixed in this highly soluble pH region, the solubility of oxo acid ions such as silicate ions and aluminate ions decreases, and these composites precipitate and grow into fine particles, or seed particles. It grows on the top and particle growth occurs. Therefore, it is not always necessary to perform pH control as in the conventional method for precipitation and growth of fine particles.

The composite ratio of silica and an inorganic compound other than silica in the first step is that the inorganic compound relative to silica is converted to oxide (MOX), and the molar ratio of MOX / SiO ₂ is 0.05 to 2.0, preferably It is desirable to be within the range of 0.2 to 2.0. Within this range, the pore volume of the porous particles increases as the proportion of silica decreases. However, even when the molar ratio exceeds 2.0, the pore volume of the porous particles hardly increases. On the other hand, when the molar ratio is less than 0.05, the pore volume becomes small. When preparing hollow particles, the molar ratio of MOX / SiO ₂ is preferably in the range of 0.25 to 2.0.

Second step: Removal of inorganic compound other than silica from porous particles In the second step, inorganic compounds other than silica (elements other than silicon and oxygen) are obtained from the porous particle precursor obtained in the first step. At least a portion is selectively removed. As a specific removal method, the inorganic compound in the porous particle precursor is dissolved and removed using a mineral acid or an organic acid, or is contacted with a cation exchange resin for ion exchange removal.

The porous particle precursor obtained in the first step is a particle having a network structure in which silicon and an inorganic compound constituent element are bonded through oxygen. By removing the inorganic compound (elements other than silicon and oxygen) from the porous particle precursor in this way, porous particles having a larger porosity and a larger pore volume can be obtained. Further, if the amount of removing the inorganic oxide (elements other than silicon and oxygen) from the porous particle precursor is increased, the hollow particles can be prepared.

In addition, prior to removing inorganic compounds other than silica from the porous particle precursor, fluorine-substituted, obtained by dealkalizing an alkali metal salt of silica into the porous particle precursor dispersion obtained in the first step. It is preferable to add a silicic acid solution containing an alkyl group-containing silane compound or a hydrolyzable organosilicon compound to form a silica protective film. The thickness of the silica protective film may be 0.5 to 15 nm. Even if the silica protective film is formed, the protective film in this step is porous and thin, so that it is possible to remove inorganic compounds other than silica described above from the porous particle precursor.

By forming such a silica protective film, inorganic compounds other than silica can be removed from the porous particle precursor while maintaining the particle shape. Further, when forming the silica coating layer described later, the pores of the porous particles are not blocked by the coating layer, and therefore the silica coating layer described later is formed without reducing the pore volume. Can do. Note that when the amount of the inorganic compound to be removed is small, the particles are not broken, and thus it is not always necessary to form a protective film.

Further, when preparing hollow particles, it is desirable to form this silica protective film. When preparing the hollow particles, the inorganic compound is removed to obtain a hollow particle precursor composed of a silica protective film, a solvent in the silica protective film, and an undissolved porous solid content. When a coating layer to be described later is formed on the precursor, the formed coating layer becomes a particle wall to form hollow particles.

The amount of the silica source added for forming the silica protective film is preferably small as long as the particle shape can be maintained. If the amount of the silica source is too large, the silica protective film becomes too thick, and it may be difficult to remove inorganic compounds other than silica from the porous particle precursor. The hydrolyzable organosilicon compound used for forming the silica protective film includes a general formula RnSi (OR ′) _4-n [R, R ′: hydrocarbon such as alkyl group, aryl group, vinyl group, acrylic group, etc. An alkoxysilane represented by a group, n = 0, 1, 2, or 3] can be used. In particular, tetraalkoxysilanes such as fluorine-substituted tetramethoxysilane, tetraethoxysilane, and tetraisopropoxysilane are preferably used.

As an addition method, a solution obtained by adding a small amount of alkali or acid as a catalyst to a mixed solution of these alkoxysilane, pure water, and alcohol is added to the dispersion of the porous particles, and the alkoxysilane is hydrolyzed. The produced silicic acid polymer is deposited on the surface of the inorganic oxide particles. At this time, alkoxysilane, alcohol, and catalyst may be simultaneously added to the dispersion. As the alkali catalyst, ammonia, an alkali metal hydroxide, or an amine can be used. As the acid catalyst, various inorganic acids and organic acids can be used.

When the dispersion medium of the porous particle precursor is water alone or the ratio of water to the organic solvent is high, a silica protective film can be formed using a silicic acid solution. When a silicic acid solution is used, a predetermined amount of the silicic acid solution is added to the dispersion, and at the same time an alkali is added to deposit the silicic acid solution on the surface of the porous particles. In addition, you may produce a silica protective film together using a silicic acid liquid and the said alkoxysilane.

Third step: Formation of silica coating layer In the third step, the porous particle dispersion prepared in the second step (in the case of hollow particles, the hollow particle precursor dispersion) contains a fluorine-substituted alkyl group-containing silane compound. By adding a hydrolyzable organosilicon compound or silicic acid solution, the surface of the particles is coated with a polymer such as a hydrolyzable organosilicon compound or silicic acid solution to form a silica coating layer.

Examples of the hydrolyzable organosilicon compound used for forming the silica coating layer include the general formula RnSi (OR ′) _4-n [R, R ′: alkyl group, aryl group, vinyl group, acrylic group as described above. Etc., and alkoxysilanes represented by n = 0, 1, 2, or 3] can be used. In particular, tetraalkoxysilanes such as tetramethoxysilane, tetraethoxysilane, and tetraisopropoxysilane are preferably used.

As an addition method, a solution obtained by adding a small amount of alkali or acid as a catalyst to a mixed solution of these alkoxysilanes, pure water, and alcohol is used as a dispersion of the porous particles (in the case of hollow particles, hollow particle precursor). In addition, the silicic acid polymer produced by hydrolyzing alkoxysilane is deposited on the surface of the porous particles (in the case of hollow particles, hollow particle precursors). At this time, alkoxysilane, alcohol, and catalyst may be simultaneously added to the dispersion. As the alkali catalyst, ammonia, an alkali metal hydroxide, or an amine can be used. As the acid catalyst, various inorganic acids and organic acids can be used.

When the dispersion medium of the porous particles (cavity particle precursor in the case of hollow particles) is water alone or a mixed solvent with an organic solvent and the mixed solvent has a high ratio of water to the organic solvent, a silicate solution You may form a coating layer using. The silicic acid solution is an aqueous solution of a low silicic acid polymer obtained by dealkalizing an aqueous solution of an alkali metal silicate such as water glass by ion exchange treatment.

The silicic acid solution is added to the dispersion of porous particles (in the case of hollow particles, hollow particle precursors), and at the same time, alkali is added to make the low-silicic acid polymer into porous particles (in the case of hollow particles, hollow particle precursors). ) Deposit on the surface. In addition, you may use a silicic acid liquid for the coating layer formation in combination with the said alkoxysilane. The amount of the organosilicon compound or silicic acid solution used for forming the coating layer may be such that the surface of the colloidal particles can be sufficiently covered, and the finally obtained silica coating layer has a thickness of 1 to 20 nm. In such an amount, it is added in a dispersion of porous particles (in the case of hollow particles, hollow particle precursor) in a dispersion. When the silica protective film is formed, the organosilicon compound or the silicate solution is added in such an amount that the total thickness of the silica protective film and the silica coating layer is in the range of 1 to 20 nm.

Next, the particle dispersion having the coating layer formed thereon is heat-treated. By the heat treatment, in the case of porous particles, the silica coating layer covering the surface of the porous particles is densified, and a dispersion of composite particles in which the porous particles are coated with the silica coating layer is obtained. In the case of the hollow particle precursor, the formed coating layer is densified to form hollow particle walls, and a dispersion of hollow particles having cavities filled with a solvent, gas, or porous solid content is obtained.

The heat treatment temperature at this time is not particularly limited as long as it can close the fine pores of the silica coating layer, and is preferably in the range of 80 to 300 ° C. When the heat treatment temperature is less than 80 ° C., the fine pores of the silica coating layer may not be completely closed and densified, and the treatment time may take a long time. Further, when the heat treatment temperature exceeds 300 ° C. for a long time, fine particles may be formed, and the effect of low refractive index may not be obtained.

The refractive index of the inorganic fine particles thus obtained is as low as less than 1.42. Such inorganic fine particles are presumed to have a low refractive index because the porosity inside the porous particles is maintained or the inside is hollow. Further, it is possible to use commercially available the SiO ₂ particles. Specific examples of commercially available particles include P-4 manufactured by Catalyst Chemical Industry Co., Ltd.

The content (mass) of the hollow spherical silica-based fine particles A having an outer shell layer, which is porous or hollow, in the low refractive index layer coating solution is preferably 10 to 80% by mass, more preferably 20 to 60% by mass. % By mass.

(Tetraalkoxysilane compound or hydrolyzate thereof)
The low refractive index layer preferably contains a tetraalkoxysilane compound or a hydrolyzate thereof as a sol-gel material. As the material for the low refractive index layer, it is also preferable to use a silicon oxide having an organic group in addition to the inorganic silicon oxide. These are generally called sol-gel materials, but metal alcoholates, organoalkoxy metal compounds and hydrolysates thereof can be used. In particular, alkoxysilane, organoalkoxysilane and its hydrolyzate are preferable. Examples of these include tetraalkoxysilane (tetramethoxysilane, tetraethoxysilane, etc.), alkyltrialkoxysilane (methyltrimethoxysilane, ethyltrimethoxysilane, etc.), aryltrialkoxysilane (phenyltrimethoxysilane, etc.), dialkyl. Examples thereof include dialkoxysilane and diaryl dialkoxysilane. Tetraalkoxysilane and its hydrolyzate are particularly preferable.

In addition, organoalkoxysilanes having various functional groups (vinyl trialkoxysilane, methylvinyl dialkoxysilane, γ-glycidyloxypropyltrialkoxysilane, γ-glycidyloxypropylmethyl dialkoxysilane, β- (3,4-epoxy) Dicyclohexyl) ethyltrialkoxysilane, γ-methacryloyloxypropyltrialkoxysilane, γ-aminopropyltrialkoxysilane, γ-mercaptopropyltrialkoxysilane, γ-chloropropyltrialkoxysilane, etc.), perfluoroalkyl group-containing silane compounds ( For example, it is also preferable to use (heptadecafluoro-1,1,2,2-tetradecyl) triethoxysilane, 3,3,3-trifluoropropyltrimethoxysilane, etc.). In particular, the use of a fluorine-containing silane compound is preferable in terms of lowering the refractive index of the layer and imparting water and oil repellency.

When hydrolyzing the tetraalkoxysilane, it is preferable to mix the inorganic fine particles in order to increase the film strength. The low refractive index layer preferably contains the silicon oxide and the following silane coupling agent.

Specific examples of the silane coupling agent include methyltrimethoxysilane, methyltriethoxysilane, methyltrimethoxyethoxysilane, methyltriacetoxysilane, methyltributoxysilane, ethyltrimethoxysilane, ethyltriethoxysilane, vinyltriethoxysilane. Methoxysilane, vinyltriethoxysilane, vinyltriacetoxysilane, vinyltrimethoxyethoxysilane, phenyltrimethoxysilane, phenyltriethoxysilane, phenyltriacetoxysilane, γ-chloropropyltrimethoxysilane, γ-chloropropyltriethoxysilane, γ-chloropropyltriacetoxysilane, 3,3,3-trifluoropropyltrimethoxysilane, γ-glycidyloxypropyltrimethoxysilane, γ-glycidyloxy Cypropyltriethoxysilane, γ- (β-glycidyloxyethoxy) propyltrimethoxysilane, β- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, β- (3,4-epoxycyclohexyl) ethyltriethoxysilane Γ-acryloyloxypropyltrimethoxysilane, γ-methacryloyloxypropyltrimethoxysilane, γ-aminopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, γ-mercaptopropyltrimethoxysilane, γ-mercaptopropyltriethoxysilane N-β- (aminoethyl) -γ-aminopropyltrimethoxysilane and β-cyanoethyltriethoxysilane.

Examples of silane coupling agents having a disubstituted alkyl group with respect to silicon include dimethyldimethoxysilane, phenylmethyldimethoxysilane, dimethyldiethoxysilane, phenylmethyldiethoxysilane, and γ-glycidyloxypropylmethyldiethoxysilane. Γ-glycidyloxypropylmethyldimethoxysilane, γ-glycidyloxypropylphenyldiethoxysilane, γ-chloropropylmethyldiethoxysilane, dimethyldiacetoxysilane, γ-acryloyloxypropylmethyldimethoxysilane, γ-acryloyloxypropylmethyldi Ethoxysilane, γ-methacryloyloxypropylmethyldimethoxysilane, γ-methacryloyloxypropylmethyldiethoxysilane, γ-mercaptopropylmethyldimethyl Kishishiran, .gamma.-mercaptopropyl methyl diethoxy silane, .gamma.-aminopropyl methyl dimethoxy silane, .gamma.-aminopropyl methyl diethoxy silane, methyl vinyl dimethoxy silane, and methyl vinyl diethoxy silane.

Of these, vinyltrimethoxysilane, vinyltriethoxysilane, vinyltriacetoxysilane, vinyltrimethoxyethoxysilane, γ-acryloyloxypropyltrimethoxysilane and γ-methacryloyloxypropyltrimethoxysilane having a double bond in the molecule. Γ-acryloyloxypropylmethyldimethoxysilane, γ-acryloyloxypropylmethyldiethoxysilane, γ-methacryloyloxypropylmethyldimethoxysilane, γ-methacryloyloxypropylmethyldiethoxy are those having a disubstituted alkyl group with respect to silicon. Silane, methylvinyldimethoxysilane and methylvinyldiethoxysilane are preferred, γ-acryloyloxypropyltrimethoxysilane and γ-methacryloyloxy Particularly preferred are propyltrimethoxysilane, γ-acryloyloxypropylmethyldimethoxysilane, γ-acryloyloxypropylmethyldiethoxysilane, γ-methacryloyloxypropylmethyldimethoxysilane and γ-methacryloyloxypropylmethyldiethoxysilane.

Specific examples of the silane coupling agent include KBM-303, KBM-403, KBM-402, KBM-403, KBM-1403, KBM-502, KBM-503, KBE-502, KBE- manufactured by Shin-Etsu Chemical Co., Ltd. 503, KBM-603, KBE-603, KBM-903, KBE-903, KBE-9103, KBM-802, KBM-803 and the like.

Two or more coupling agents may be used in combination. In addition to the silane coupling agents shown above, other silane coupling agents may be used. Other silane coupling agents include alkyl esters of orthosilicate (eg, methyl orthosilicate, ethyl orthosilicate, n-propyl orthosilicate, i-propyl orthosilicate, n-butyl orthosilicate, sec-butyl orthosilicate, orthosilicate). Acid t-butyl) and hydrolysates thereof.

The low refractive index layer can also contain a polymer in an amount of 5 to 50% by mass. The polymer has a function of adhering fine particles and maintaining the structure of a low refractive index layer including voids. The amount of the polymer used is adjusted so that the strength of the low refractive index layer can be maintained without filling the voids. The amount of the polymer is preferably 10 to 30% by mass with respect to the total amount of the low refractive index layer. In order to adhere the fine particles with the polymer, (1) the polymer is bonded to the surface treatment agent of the fine particles, (2) the fine particles are used as a core, and a polymer shell is formed around the fine particles. It is preferable to use a polymer as the binder. The polymer to be bonded to the surface treating agent (1) is preferably the shell polymer (2) or the binder polymer (3). The polymer (2) is preferably formed around the fine particles by a polymerization reaction before preparing the coating solution for the low refractive index layer. The polymer (3) is preferably formed by adding a monomer to the coating solution for the low refractive index layer, and by polymerization reaction simultaneously with or after the coating of the low refractive index layer. It is preferable to implement a combination of two or all of the above (1) to (3), and to implement a combination of (1) and (3), or (1) to (3) all combinations. Particularly preferred. (1) Surface treatment, (2) shell, and (3) binder will be described sequentially.

(1) Surface treatment It is preferable that the fine particles (particularly inorganic fine particles) are subjected to a surface treatment to improve the affinity with the polymer. The surface treatment can be classified into physical surface treatment such as plasma discharge treatment and corona discharge treatment, and chemical surface treatment using a coupling agent. It is preferable to carry out by chemical surface treatment alone or a combination of physical surface treatment and chemical surface treatment. As the coupling agent, an organoalkoxy metal compound (eg, titanium coupling agent, silane coupling agent) is preferably used. When the fine particles are made of SiO _{2, the} surface treatment with the above-described silane coupling agent can be carried out particularly effectively.

The surface treatment with the coupling agent can be carried out by adding the coupling agent to the fine particle dispersion and leaving the dispersion at a temperature from room temperature to 60 ° C. for several hours to 10 days. In order to accelerate the surface treatment reaction, inorganic acids (for example, sulfuric acid, hydrochloric acid, nitric acid, chromic acid, hypochlorous acid, boric acid, orthosilicic acid, phosphoric acid, carbonic acid), organic acids (for example, acetic acid, polyacrylic acid, Benzenesulfonic acid, phenol, polyglutamic acid), or salts thereof (eg, metal salts, ammonium salts) may be added to the dispersion.

(2) Shell The polymer forming the shell is preferably a polymer having a saturated hydrocarbon as the main chain. A polymer containing a fluorine atom in the main chain or side chain is preferred, and a polymer containing a fluorine atom in the side chain is more preferred. Polyacrylic acid esters or polymethacrylic acid esters are preferred, and esters of fluorine-substituted alcohols with polyacrylic acid or polymethacrylic acid are most preferred. The refractive index of the shell polymer decreases as the content of fluorine atoms in the polymer increases. In order to reduce the refractive index of the low refractive index layer, the shell polymer preferably contains 35 to 80% by mass of fluorine atoms, and more preferably contains 45 to 75% by mass of fluorine atoms. The polymer containing a fluorine atom is preferably synthesized by a polymerization reaction of an ethylenically unsaturated monomer containing a fluorine atom. Examples of ethylenically unsaturated monomers containing fluorine atoms include fluoroolefins (eg, fluoroethylene, vinylidene fluoride, tetrafluoroethylene, hexafluoropropylene, perfluoro-2,2-dimethyl-1,3-dioxole), Examples thereof include esters of fluorinated vinyl ethers and fluorine-substituted alcohols with acrylic acid or methacrylic acid.

The polymer forming the shell may be a copolymer comprising a repeating unit containing a fluorine atom and a repeating unit not containing a fluorine atom. The repeating unit containing no fluorine atom is preferably obtained by a polymerization reaction of an ethylenically unsaturated monomer containing no fluorine atom. Examples of ethylenically unsaturated monomers that do not contain fluorine atoms include olefins (eg, ethylene, propylene, isoprene, vinyl chloride, vinylidene chloride), acrylic esters (eg, methyl acrylate, ethyl acrylate, 2-acrylic acid 2- Ethyl hexyl), methacrylic acid esters (for example, methyl methacrylate, ethyl methacrylate, butyl methacrylate, ethylene glycol dimethacrylate), styrene and its derivatives (for example, styrene, divinylbenzene, vinyl toluene, α-methyl styrene), vinyl ether ( For example, methyl vinyl ether), vinyl esters (for example, vinyl acetate, vinyl propionate, vinyl cinnamate), acrylamide (for example, N-tertbutylacrylamide, N-cyclohexylacrylic) Amides), methacrylamide and acrylonitrile.

When the binder polymer (3) described later is used in combination, a crosslinkable functional group may be introduced into the shell polymer to chemically bond the shell polymer and the binder polymer by crosslinking. The shell polymer may have crystallinity. When the glass transition temperature (Tg) of the shell polymer is higher than the temperature at the time of forming the low refractive index layer, it is easy to maintain microvoids in the low refractive index layer. However, if Tg is higher than the temperature at which the low refractive index layer is formed, the fine particles are not fused, and the low refractive index layer may not be formed as a continuous layer (resulting in a decrease in strength). In that case, it is desirable to use a binder polymer (3) described later in combination, and form the low refractive index layer as a continuous layer with the binder polymer. By forming a polymer shell around the fine particles, core-shell fine particles are obtained. The core-shell fine particles preferably contain 5 to 90% by volume, more preferably 15 to 80% by volume of a core composed of inorganic fine particles. Two or more kinds of core-shell fine particles may be used in combination. Further, inorganic fine particles having no shell and core-shell particles may be used in combination.

(3) Binder The binder polymer is preferably a polymer having a saturated hydrocarbon or polyether as the main chain, and more preferably a polymer having a saturated hydrocarbon as the main chain. The binder polymer is preferably crosslinked. The polymer having a saturated hydrocarbon as the main chain is preferably obtained by a polymerization reaction of an ethylenically unsaturated monomer. In order to obtain a crosslinked binder polymer, it is preferable to use a monomer having two or more ethylenically unsaturated groups. Examples of monomers having two or more ethylenically unsaturated groups include esters of polyhydric alcohols and (meth) acrylic acid (eg, ethylene glycol di (meth) acrylate, 1,4-dichlorohexane diacrylate, pentaerythritol). Tetra (meth) acrylate, pentaerythritol tri (meth) acrylate, trimethylolpropane tri (meth) acrylate, trimethylolethane tri (meth) acrylate, dipentaerythritol tetra (meth) acrylate, dipentaerythritol penta (meth) acrylate, Pentaerythritol hexa (meth) acrylate, 1,2,3-cyclohexanetetramethacrylate, polyurethane polyacrylate, polyester polyacrylate), vinylbenzene and its derivatives For example, 1,4-divinylbenzene, 4-vinylbenzoic acid-2-acryloyl ethyl ester, 1,4-divinylcyclohexanone), vinyl sulfone (eg divinyl sulfone), acrylamide (eg methylene bisacrylamide) and methacrylamide Can be mentioned. The polymer having a polyether as the main chain is preferably synthesized by a ring-opening polymerization reaction of a polyfunctional epoxy compound. Instead of or in addition to the monomer having two or more ethylenically unsaturated groups, a crosslinked structure may be introduced into the binder polymer by the reaction of a crosslinkable group. Examples of crosslinkable functional groups include isocyanate groups, epoxy groups, aziridine groups, oxazoline groups, aldehyde groups, carbonyl groups, hydrazine groups, carboxy groups, methylol groups, and active methylene groups. Vinylsulfonic acid, acid anhydride, cyanoacrylate derivative, melamine, etherified methylol, ester and urethane can also be used as a monomer for introducing a crosslinked structure. A functional group that exhibits crosslinkability as a result of the decomposition reaction, such as a block isocyanate group, may be used. The cross-linking group is not limited to the above compound, and may be one that exhibits reactivity as a result of decomposition of the functional group. As the polymerization initiator used for the polymerization reaction and the crosslinking reaction of the binder polymer, a thermal polymerization initiator or a photopolymerization initiator is used, and the photopolymerization initiator is more preferable. Examples of photopolymerization initiators include acetophenones, benzoins, benzophenones, phosphine oxides, ketals, anthraquinones, thioxanthones, azo compounds, peroxides, 2,3-dialkyldione compounds, disulfide compounds , Fluoroamine compounds and aromatic sulfoniums. Examples of acetophenones include 2,2-diethoxyacetophenone, p-dimethylacetophenone, 1-hydroxydimethylphenyl ketone, 1-hydroxycyclohexyl phenyl ketone, 2-methyl-4-methylthio-2-morpholinopropiophenone and 2 -Benzyl-2-dimethylamino-1- (4-morpholinophenyl) -butanone. Examples of benzoins include benzoin methyl ether, benzoin ethyl ether, and benzoin isopropyl ether. Examples of benzophenones include benzophenone, 2,4-dichlorobenzophenone, 4,4-dichlorobenzophenone and p-chlorobenzophenone. Examples of phosphine oxides include 2,4,6-trimethylbenzoyldiphenylphosphine oxide.

The binder polymer is preferably formed by adding a monomer to the coating solution for the low refractive index layer, and at the same time as or after the coating of the low refractive index layer, by a polymerization reaction (further crosslinking reaction if necessary). Even if a small amount of polymer (for example, polyvinyl alcohol, polyoxyethylene, polymethyl methacrylate, polymethyl acrylate, diacetyl cellulose, triacetyl cellulose, nitrocellulose, polyester, alkyd resin) is added to the coating solution for the low refractive index layer Good.

Further, the low refractive index layer may be a low refractive index layer formed by crosslinking a fluorine-containing resin that is crosslinked by heat or ionizing radiation (hereinafter also referred to as “fluorine-containing resin before crosslinking”).

Preferred examples of the fluorine-containing resin before crosslinking include a fluorine-containing copolymer formed from a fluorine-containing vinyl monomer and a monomer for imparting a crosslinkable group. Specific examples of the fluorine-containing vinyl monomer unit include, for example, fluoroolefins (for example, fluoroethylene, vinylidene fluoride, tetrafluoroethylene, hexafluoroethylene, hexafluoropropylene, perfluoro-2,2-dimethyl-1,3 -Dioxole, etc.), (meth) acrylic acid partial or fully fluorinated alkyl ester derivatives (for example, Biscoat 6FM (produced by Osaka Organic Chemical), M-2020 (produced by Daikin), etc.), fully or partially fluorinated vinyl ethers, etc. Is mentioned. Examples of the monomer for imparting a crosslinkable group include glycidyl methacrylate, vinyltrimethoxysilane, γ-methacryloyloxypropyltrimethoxysilane, vinyl glycidyl ether, and other vinyl monomers having a crosslinkable functional group in advance in the molecule. , Vinyl monomers having a carboxy group, a hydroxy group, an amino group, a sulfonic acid group, etc. (for example, (meth) acrylic acid, methylol (meth) acrylate, hydroxyalkyl (meth) acrylate, allyl acrylate, hydroxyalkyl vinyl ether, hydroxyalkyl allyl) Ether, etc.). The latter can introduce a crosslinked structure by adding a compound having a group that reacts with a functional group in the polymer and one or more reactive groups after copolymerization, as disclosed in JP-A-10-25388 and 10-147739. In the issue. Examples of the crosslinkable group include acryloyl, methacryloyl, isocyanate, epoxy, aziridine, oxazoline, aldehyde, carbonyl, hydrazine, carboxy, methylol, and active methylene group. When the fluorine-containing copolymer is crosslinked by heating with a crosslinking group that reacts by heating, or a combination of an ethylenically unsaturated group and a thermal radical generator or an epoxy group and a thermal acid generator, it is a thermosetting type. In the case of crosslinking by irradiation with light (preferably ultraviolet rays, electron beams, etc.) by a combination of an ethylenically unsaturated group and a photo radical generator, or an epoxy group and a photo acid generator, the ionizing radiation curable type is used.

Further, in addition to the above monomers, a fluorine-containing copolymer formed by using a monomer other than the fluorine-containing vinyl monomer and the monomer for imparting a crosslinkable group may be used as the fluorine-containing resin before crosslinking. The monomer that can be used in combination is not particularly limited. For example, olefins (ethylene, propylene, isoprene, vinyl chloride, vinylidene chloride, etc.), acrylic esters (methyl acrylate, methyl acrylate, ethyl acrylate, 2-acrylic acid 2- Ethyl hexyl), methacrylic acid esters (methyl methacrylate, ethyl methacrylate, butyl methacrylate, ethylene glycol dimethacrylate, etc.), styrene derivatives (styrene, divinylbenzene, vinyl toluene, α-methyl styrene, etc.), vinyl ethers (methyl vinyl ether) Etc.), vinyl esters (vinyl acetate, vinyl propionate, vinyl cinnamate, etc.), acrylamides (N-tertbutylacrylamide, N-cyclohexylacrylamide, etc.), methacrylamides, Ronitoriru derivatives and the like can be mentioned. In addition, it is also preferable to introduce a polyorganosiloxane skeleton or a perfluoropolyether skeleton into the fluorinated copolymer in order to impart slipperiness and antifouling properties. For example, polyorganosiloxane or perfluoropolyether having an acrylic group, methacrylic group, vinyl ether group, styryl group or the like at the terminal is polymerized with the above monomer, and polyorganosiloxane or perfluoropolyester having a radical generating group at the terminal. It can be obtained by polymerization of the above monomers with ether, reaction of a polyorganosiloxane or perfluoropolyether having a functional group with a fluorine-containing copolymer, or the like.

The proportion of each monomer used to form the fluorinated copolymer before cross-linking is preferably 20 to 70 mol%, more preferably 40 to 70 mol% of the fluorinated vinyl monomer, The amount of the monomer is preferably 1 to 20 mol%, more preferably 5 to 20 mol%, and the other monomer used in combination is preferably 10 to 70 mol%, more preferably 10 to 50 mol%.

The fluorine-containing copolymer can be obtained by polymerizing these monomers in the presence of a radical polymerization initiator by means of solution polymerization, bulk polymerization, emulsion polymerization, suspension polymerization or the like.

Fluorine-containing resin before crosslinking is commercially available and can be used. Examples of commercially available fluorine-containing resins before cross-linking include Cytop (Asahi Glass), Teflon (registered trademark) AF (DuPont), polyvinylidene fluoride, Lumiflon (Asahi Glass), Opstar (JSR), etc. Can be mentioned.

The low refractive index layer comprising a crosslinked fluorine-containing resin as a constituent component preferably has a dynamic friction coefficient in the range of 0.03 to 0.15 and a contact angle with water in the range of 90 to 120 degrees.

(Cationically polymerizable compound)
The low refractive index layer may contain a cationically polymerizable compound as a binder. Any cationically polymerizable compound can be used as long as it undergoes cationic polymerization by irradiation with energy active rays or heat to form a resin. Specific examples include an epoxy group, a cyclic ether group, a cyclic acetal group, a cyclic lactone group, a cyclic thioether group, a spiro orthoester compound, and a vinyloxo group. Among them, a compound having a functional group such as an epoxy group or a vinyl ether group is preferably used in the present embodiment. Examples of the cationically polymerizable compound having an epoxy group or a vinyl ether group include phenyl glycidyl ether, ethylene glycol diglycidyl ether, glycerin diglycidyl ether, vinylcyclohexene dioxide, limonene dioxide, 3,4-epoxycyclohexylmethyl-3 ′. , 4'-epoxycyclohexanecarboxylate, bis- (6-methyl-3,4-epoxycyclohexyl) adipate, 2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, diethylene glycol divinyl ether, polyethylene glycol divinyl ether, 1 , 4-cyclohexanedimethanol divinyl ether and the like.

Also, oxetane compounds can be mentioned. The oxetane compound may be a compound having at least one oxetane ring in the molecule.

Furthermore, if necessary, a (co) polymer containing a monomer having a hydrogen bond forming group and a reactive polymer having an oxetanyl group in the main chain or side chain and having a number average molecular weight of 20,000 or more can also be used. From the viewpoint of stability of the low refractive index layer coating composition, the above cationic polymerizable compound is preferably 15% by mass or more and less than 70% by mass in the solid content in the low refractive layer coating composition.

(Cationic polymerization accelerator)
Examples of the compound that accelerates the polymerization of the cationic polymerizable compound include known acids and photoacid generators. Examples of the photoacid generator include a cationic polymerization photoinitiator, a dye photodecoloring agent, a photochromic agent, a known compound used in a microresist, and a mixture thereof. Specific examples include onium compounds, organic halogen compounds, and disulfone compounds, and onium compounds are preferable. As the onium compound, diazonium salts, sulfonium salts, iodonium salts and the like represented by the following formulas are preferably used.

ArN ₂ ⁺ Z ⁻ ,
(R) ₃ S ⁺ Z ⁻ ,
(R) ₂ I ⁺ Z ⁻
In the formula, Ar represents an aryl group, R represents an alkyl group having an aryl group or having 1 to 20 carbon atoms, when appearing more than R are times in one molecule may be different from each other in the same, Z ^- is Represents a non-basic and non-nucleophilic anion.

In each of the above formulas, the aryl group represented by Ar or R is also typically phenyl or naphthyl, and these may be substituted with an appropriate group. Specific examples of the anion represented by Z ⁻ include tetrafluoroborate ion (BF ₄ ⁻ ), tetrakis (pentafluorophenyl) borate ion (B (C ₆ F ₅ ) ₄ ⁻ ), hexafluorophosphate ion. (PF ₆ ⁻ ), hexafluoroarsenate ion (AsF ₆ ⁻ ), hexafluoroantimonate ion (SbF ₆ ⁻ ), hexachloroantimonate ion (SbCl ₆ ⁻ ), hydrogen sulfate ion (HSO ₄ ⁻ ), perchloric acid Ions (ClO ₄ ⁻ ) and the like.

Other onium compounds include ammonium salts, iminium salts, phosphonium salts, arsonium salts, selenonium salts, boron salts and the like.

Of these, diazonium salts, iodonium salts, sulfonium salts, and iminium salts are preferable from the viewpoint of the material stability of the compound.

Since many of these compounds are commercially available, such commercially available products can be used. Commercially available initiators include, for example, “Syracure UVI-6990” (trade name) sold by Dow Chemical Japan Co., Ltd., and “Adekaoptomer SP-150” (trade name) sold by ADEKA Co., Ltd. Product name), “Adekaoptomer SP-300” (product name), “RHODORSIL PHOTOINITIAOR 2074” (product name) sold by Rhodia Japan Co., Ltd., and the like.

As the acid, Bronsted acid such as hydrochloric acid, sulfuric acid, nitric acid, phosphoric acid or the like, or organic acid such as acetic acid, formic acid, methanesulfonic acid, trifluoromethanesulfonic acid, paratoluenesulfonic acid, dibutyltin dilaurate, Examples thereof include Lewis acids such as dibutyltin diacetate, dibutyltin dioctate, triisopropoxyaluminum, tetrabutoxyzirconium, and tetrabutoxytitanate.

Aromatic polycarboxylic acids such as pyromellitic acid, pyromellitic anhydride, trimellitic acid, trimellitic anhydride, phthalic acid, phthalic anhydride, or anhydrides thereof, maleic acid, maleic anhydride, succinic acid, succinic anhydride Aliphatic polyvalent carboxylic acid or anhydride thereof such as

As the acid, only one kind may be used, or two or more kinds may be used in combination. These acids and photoacid generators are preferably added in an amount of 0.1 to 20 parts by mass, more preferably 0.5 to 15 parts by mass, with respect to 100 parts by mass of the cationic polymerizable compound. is there. When the addition amount is in the above range, it is preferable from the viewpoint of stability of the curable composition, polymerization reactivity, and the like.

(Radically polymerizable compound)
The low refractive index layer can also contain a radical polymerizable compound as a binder. Examples of the radical polymerizable group include ethylenically unsaturated groups such as a (meth) acryloyl group, a vinyloxy group, a styryl group, and an allyl group, and among them, a compound having a (meth) acryloyl group is preferable. The radical polymerizable compound preferably contains a polyfunctional monomer containing two or more radical polymerizable groups in the molecule. The polyfunctional acrylate is preferably selected from the group consisting of pentaerythritol polyfunctional acrylate, dipentaerythritol polyfunctional acrylate, pentaerythritol polyfunctional methacrylate, and dipentaerythritol polyfunctional methacrylate. The addition amount of the radical polymerizable compound is preferably 15% by mass or more and less than 70% by mass in the solid content in the low refractive layer coating composition from the viewpoint of the stability of the low refractive layer coating composition.

(Radical polymerization accelerator)
In order to accelerate the curing of the radical polymerizable compound, it is preferable to use a photopolymerization initiator in combination with the radical polymerizable compound. When a photopolymerization initiator and a radical polymerizable compound are used in combination, the photopolymerization initiator and the radical polymerizable compound are preferably contained in a mass ratio of 20: 100 to 0.01: 100.

Specific examples of the photopolymerization initiator include acetophenone, benzophenone, hydroxybenzophenone, Michler ketone, α-amyloxime ester, thioxanthone, and derivatives thereof, but are not particularly limited thereto.

The low refractive index layer is a gravure coater, a dip coater, a reverse coater, a wire bar coater, a die coater, a known method such as an inkjet method, and the above coating composition for forming the low refractive index layer is applied, and after coating, It is formed by heat drying and curing treatment as necessary.

The coating amount is suitably 0.05 to 100 μm, preferably 0.1 to 50 μm, as the wet film thickness. Further, the solid content concentration of the coating composition is adjusted so that the dry film thickness becomes the above film thickness.

Further, it may include a step of performing heat treatment at a temperature of 50 to 160 ° C. after forming the low refractive index layer. The period of the heat treatment may be appropriately determined depending on the set temperature. For example, if it is 50 ° C., preferably it is a period of 3 days or more and less than 30 days, and if it is 160 ° C., a range of 10 minutes or more and 1 day or less is preferable. . Examples of the curing method include a method of thermosetting by heating, a method of curing by irradiation with light such as ultraviolet rays, and the like. In the case of thermosetting, the heating temperature is preferably 50 to 300 ° C, preferably 60 to 250 ° C, more preferably 80 to 150 ° C. In the case of curing by light irradiation, the exposure amount of the irradiation light is preferably 10 mJ / cm ² to 1 J / cm ² , and more preferably 100 to 500 mJ / cm ² .

Here, the wavelength range of the irradiated light is not particularly limited, but light having a wavelength in the ultraviolet region is preferably used. Specifically, a low pressure mercury lamp, a medium pressure mercury lamp, a high pressure mercury lamp, an ultrahigh pressure mercury lamp, a carbon arc lamp, a metal halide lamp, a xenon lamp, or the like can be used.

<High refractive index layer and medium refractive index layer>
The high refractive index layer and the middle refractive index layer preferably contain metal oxide fine particles. The kind of metal oxide fine particles is not particularly limited, and Ti, Zr, Sn, Sb, Cu, Fe, Mn, Pb, Cd, As, Cr, Hg, Zn, Al, Mg, Si, P and S A metal oxide having at least one element selected from the group consisting of Al, In, Sn, Sb, Nb, a halogen element, Ta and the like is doped with a minute amount of atoms. May be. A mixture of these may also be used. Among them, the main component is at least one metal oxide fine particle selected from organic titanium compounds, zirconium oxide, antimony oxide, tin oxide, zinc oxide, indium-tin oxide (ITO), antimony-doped tin oxide (ATO), and zinc antimonate. It is particularly preferable to use as In particular, it is preferable to contain zinc antimonate particles.

The average particle diameter of the primary particles of these metal oxide fine particles is in the range of 10 to 200 nm, particularly preferably 10 to 150 nm. The average particle diameter of the metal oxide fine particles can be measured from an electron micrograph taken with a scanning electron microscope (SEM) or the like. You may measure by the particle size distribution meter etc. which utilize a dynamic light scattering method, a static light scattering method, etc. If the particle size is too small, aggregation tends to occur and the dispersibility deteriorates. If the particle size is too large, the haze is remarkably increased. The shape of the metal oxide fine particles is preferably a rice grain shape, a spherical shape, a cubic shape, a spindle shape, a needle shape, or an indefinite shape.

Specifically, the refractive index of the high refractive index layer is preferably higher than the refractive index of the base film, and is preferably in the range of 1.5 to 2.3 when measured at 23 ° C. and a wavelength of 550 nm. The means for adjusting the refractive index of the high refractive index layer is that the kind and addition amount of the metal oxide fine particles are dominant, so that the refractive index of the metal oxide fine particles is preferably 1.80 to 2.60. More preferably, it is 1.85 to 2.50.

The refractive index of the middle refractive index layer is adjusted to be an intermediate value between the refractive index of the base film and the refractive index of the high refractive index layer. Specifically, the refractive index of the middle refractive index layer is preferably 1.55 to 1.80.

The thickness of the high refractive index layer and the middle refractive index layer is preferably 5 nm to 1 μm, more preferably 10 nm to 0.2 μm, and most preferably 30 to 100 nm.

The high refractive index layer and the medium refractive index layer preferably contain metal oxide particles as fine particles, and further contain a binder polymer.

As the binder polymer of the high refractive index layer and the medium refractive index layer, a crosslinked polymer is preferable. As an example of the crosslinked polymer, a monomer having two or more ethylenically unsaturated groups is most preferable, and examples thereof include esters of polyhydric alcohol and (meth) acrylic acid (eg, ethylene glycol di (meth) acrylate). 1,4-dichlorohexanediacrylate, pentaerythritol tetra (meth) acrylate, pentaerythritol tri (meth) acrylate, trimethylolpropane tri (meth) acrylate, trimethylolethane tri (meth) acrylate, dipentaerythritol tetra (meth) ) Acrylate, dipentaerythritol penta (meth) acrylate, pentaerythritol hexa (meth) acrylate, 1,2,3-cyclohexanetetramethacrylate, polyurethane polyacrylate, polyester polyacrylate Relate), vinylbenzene and its derivatives (eg, 1,4-divinylbenzene, 4-vinylbenzoic acid-2-acryloylethyl ester, 1,4-divinylcyclohexanone), vinylsulfone (eg, divinylsulfone), acrylamide (eg, , Methylenebisacrylamide) and methacrylamide. For the polymerization reaction of the polymer, a photopolymerization reaction or a thermal polymerization reaction can be used. A photopolymerization reaction is particularly preferable. A polymerization initiator is preferably used for the polymerization reaction. For example, the thermal polymerization initiator mentioned later used in order to form the binder polymer of a hard-coat layer, and a photoinitiator are mentioned.

A commercially available polymerization initiator may be used as the polymerization initiator. In addition to the polymerization initiator, a polymerization accelerator may be used. The addition amount of the polymerization initiator and the polymerization accelerator is preferably in the range of 0.2 to 10% by mass of the total amount of monomers. The coating liquid (dispersion of inorganic fine particles containing monomer) may be heated to promote polymerization of the monomer (or oligomer). Moreover, it may heat after the photopolymerization reaction after application | coating, and may additionally process the thermosetting reaction of the formed polymer.

The middle and high refractive index layers can be provided by coating, drying and curing on the antiglare layer as a coating layer composition by diluting the above-described components forming the middle and high refractive index layers with a solvent. As a light source for curing, any light source that generates ultraviolet rays can be used without limitation. For example, a low pressure mercury lamp, a medium pressure mercury lamp, a high pressure mercury lamp, an ultrahigh pressure mercury lamp, a carbon arc lamp, a metal halide lamp, a xenon lamp, or the like can be used. The amount of irradiation light is preferably 20 mJ / cm ² to 1 J / cm ^2, more preferably 100 to 500 mJ / cm ² .

(Reflectivity of antireflection layer)
The antireflection layer of the antiglare antireflection film has an average reflectance at 450 to 650 nm of preferably 1.5% or less, particularly preferably 1.2% or less. Further, the minimum reflectance in this range is preferably 0.00 to 0.5%.

The refractive index and film thickness of the antireflection layer can be calculated and calculated by measuring the spectral reflectance. Moreover, the reflection optical characteristic of the anti-glare antireflection film having the antireflection layer thus produced can be measured for reflectance under the condition of regular reflection at 5 degrees using a spectrophotometer. In this measurement method, after roughening the back surface on the side where the antireflection layer is not applied, the light absorption treatment is performed with a black spray, or the light absorption treatment is performed by attaching a black acrylic plate or the like. The reflectance can be measured by preventing reflection of the back light of the film. In the measurement, the transmittance at a transmittance of 550 nm is measured using a spectrophotometer with reference to air.

Further, the antiglare antireflection film according to this embodiment preferably has a flat reflection spectrum in the wavelength region of visible light. Reflective hues are often colored red and blue due to the high reflectance in the short-wavelength and long-wavelength regions in the visible light region due to the design of the antireflection layer. In contrast, when used on the surface of an image display device or the like, a neutral color tone is preferred. In this case, generally preferred reflection hue ranges are 0.17 ≦ x ≦ 0.27 and 0.07 ≦ y ≦ 0.17 on the XYZ color system (CIE1931 color system). Further, the range in which the distance Δxy of (x, y) = (0.31, 0.31) on the xy plane is 0.05 or less is preferable because it is closer to neutral with no color, and 0.03 or less is preferable. Further preferred. The color tone can be calculated from the refractive index of each layer in accordance with a conventional method in consideration of the reflectance and the color of reflected light.

<Polarizing plate>
The polarizing plate according to this embodiment using the antiglare film according to this embodiment will be described. The polarizing plate according to the present embodiment is provided with the antiglare film according to the present embodiment. Since such a polarizing plate includes the antiglare film, it improves both visibility and reduces moire fringes. The polarizing plate includes, for example, a polarizing film and a transparent protective film (polarizing plate protective film) disposed on the surface of the polarizing film, and the transparent protective film is an antiglare film according to this embodiment. Some are listed. More specifically, as shown in FIG. 4, the polarizing plate 10 has an antiglare layer 12 on the outer side and a base film 13 on the inner surface of the polarizing film 14 on the visible side. The thing by which the anti-glare film 11 is arrange | positioned is mentioned. In the polarizing plate 10, the optical film 15 is disposed on the surface of the polarizing film 14 opposite to the surface on the viewing side, and the adhesive layer 16 that can be attached to other members is disposed outside the polarizing film 14. The thing which was done is mentioned. In addition, although it does not specifically limit as the optical film 15, For example, the polarizing plate protective film etc. which are mentioned later are mentioned.

Moreover, the polarizing plate can be produced by a general method. The back surface side of the antiglare film according to the present embodiment is subjected to alkali saponification treatment, and the processed antiglare film is immersed and stretched in an iodine solution, and at least one surface of the polarizing film is completely saponified polyvinyl alcohol. It is preferable to bond using an aqueous solution.

The antiglare film may be used on the other surface, or another polarizing plate protective film may be used. For the antiglare film according to the present embodiment, the polarizing plate protective film used on the other surface contains a cellulose triacetate film or a thermoplastic acrylic resin and a cellulose ester resin as the base film described above, It is preferable to use a protective film in which the mass ratio of the thermoplastic acrylic resin to the cellulose ester resin is thermoplastic acrylic resin: cellulose ester resin = 95: 5 to 50:50. Details of the configuration are as described above, and specific examples include a non-oriented film having a retardation Ro of 590 nm and 0 to 5 nm and an Rt of −20 to +20 nm.

In addition, an optical compensation film (retardation film) having a retardation of in-plane retardation Ro of 590 nm, 20 to 70 nm, and Rt of 70 to 400 nm may be used to obtain a polarizing plate capable of widening the viewing angle. it can. Alternatively, it is preferable to use an optical compensation film having an optically anisotropic layer formed by aligning a liquid crystal compound such as a discotic liquid crystal. Also, commercially available polarizing plate protective films preferably used include KC8UX2MW, KC4UX, KC5UX, KC4UY, KC8UY, KC12UR, KC4UEW, KC8UCR-3, KC8UCR-4, KC8UCR-5, KC4FR-2, KC4FR-2, KC4FR-2, KC8FR-2 KC4UE (Konica Minolta Opto Co., Ltd.) etc. are mentioned.

A polarizing film, which is a main component of a polarizing plate, is an element that allows only light having a polarization plane in a certain direction to pass through. That is, the polarizing film is an optical element that emits incident light by converting it into polarized light. A typical polarizing film currently known is a polyvinyl alcohol polarizing film, which includes a polyvinyl alcohol film stained with iodine and a dichroic dye stained, but is not limited to this. It is not something. As the polarizing film, a polyvinyl alcohol aqueous solution is formed and dyed by uniaxially stretching or dyed, or uniaxially stretched after dyeing, and then preferably subjected to a durability treatment with a boron compound. A polarizing film having a thickness of 5 to 30 μm, preferably 8 to 15 μm is preferably used. On the surface of the polarizing film, one side of the antiglare film according to the present embodiment is bonded to form a polarizing plate. It is preferably bonded with an aqueous adhesive mainly composed of completely saponified polyvinyl alcohol or the like.

(Adhesive layer)
The pressure-sensitive adhesive layer used on one side of the protective film to be bonded to the substrate of the liquid crystal cell is preferably optically transparent and exhibits moderate viscoelasticity and adhesive properties.

Specific examples of the adhesive layer include adhesives or adhesives such as acrylic copolymers, epoxy resins, polyurethane, silicone polymers, polyethers, butyral resins, polyamide resins, polyvinyl alcohol resins, and synthetic rubbers. A film such as a drying method, a chemical curing method, a thermal curing method, a thermal melting method, a photocuring method, or the like can be formed and cured using a polymer such as the above. Among them, the acrylic copolymer can be preferably used because it is most easy to control the physical properties of the adhesive and is excellent in transparency, weather resistance, durability and the like.

<Image display device>
The antiglare film according to the present embodiment exhibits excellent performance when used in an image display device. As an image display device, a reflection type, a transmission type, a semi-transmission type liquid crystal display device, a liquid crystal display device of various drive systems such as a TN type, STN type, OCB type, VA type, IPS type, ECB type, etc., organic electroluminescence Examples include a display device having an element and a plasma display.

Among these image display devices, the use of the antiglare film according to the present embodiment for the polarizing plate of a liquid crystal display device is preferable from the viewpoint of excellent visibility. A polarizing plate according to this embodiment is shown in FIG. Moreover, by using the polarizing plate comprised from the anti-glare film which concerns on this embodiment on the rear side (backlight side) of a liquid crystal cell (FIG. 6) of a liquid crystal display device provided with a liquid crystal panel as shown in FIG. In view of excellent prevention of occurrence of moire fringes.

That is, the image forming apparatus according to the present embodiment is provided with the antiglare film according to the present embodiment. Since such an image forming apparatus is provided with the antiglare film, it improves both visibility and reduces moire fringes. Examples of the image forming apparatus include a liquid crystal cell and at least one of two polarizing plates arranged so as to sandwich the liquid crystal cell is the polarizing plate according to the above-described embodiment. More specifically, as shown in FIG. 5, the liquid crystal panel 20 has an anti-glare film 25 on the surface of the liquid crystal cell 21 on the rear (backlight) side (opposite to the viewing side surface). In such a case, a polarizing plate 28 is disposed. The liquid crystal panel 20 includes a liquid crystal cell 21 in which a polarizing plate 27 different from the polarizing plate 28 is disposed on the surface on the viewing side. Examples of the polarizing plate 27 include a polarizing plate including a clear hard coat film 24 instead of an antiglare film.

Note that the liquid crystal cell is a cell in which a liquid crystal substance is filled between a pair of electrodes. By applying a voltage to this electrode, the alignment state of the liquid crystal is changed and the amount of transmitted light is controlled. Specifically, as shown in FIG. 6, the liquid crystal cell 30 includes two stacked bodies in which an alignment film 32, a color filter 33, and a glass substrate 34 are stacked. The liquid crystal 31 is disposed between the alignment films 32 and the like. In the liquid crystal cell 30, a transparent electrode for applying a voltage to the liquid crystal 31 may be disposed between the alignment film 32 and the color filter 33.

Further, the antiglare film according to the present embodiment may be used for a touch panel member. The touch panel member according to the present embodiment is provided with the antiglare film according to the present embodiment. Since such a member for touch panels is provided with the said anti-glare film, it is compatible with the improvement of visibility and the reduction of moire fringes. Specifically, an anti-glare film with a conductive film as shown in FIG. The antiglare film 40 with a conductive film is a member for a touch panel, and includes an antiglare film including an antiglare layer 42 on the surface of the base film 41. The antiglare film includes an antiglare layer 42 on both surfaces of the base film 41. And the anti-glare film 40 with a conductive film is equipped with the transparent conductive thin film (ITO layer) 43 on one surface of this anti-glare film.

As described above, when the antiglare film according to the present embodiment is used for the touch panel member of the image display device with a touch panel, it is preferable in view of excellent visibility and durability against pen input (such as scratches caused by sliding).

<Touch panel>
An example at the time of using the anti-glare film which concerns on this embodiment for the image display apparatus with a touch panel is shown.

FIG. 8 is a schematic view of a liquid crystal display device 50 with a resistive touch panel using the antiglare film according to the present embodiment as a touch panel. The conductive antiglare film (antiglare film with conductive film) 40 is opposed to the glass substrate 53 on which the transparent conductive thin film 52 is formed so that the transparent conductive thin films face each other, and between the transparent conductive thin films By using the spacer 51, a resistive film type touch panel can be configured with a certain interval. Electrodes (not shown) are arranged at the ends of the conductive antiglare film 40 and the glass substrate 53. The resistive film type touch panel is such that the transparent conductive thin film of the conductive antiglare film 40 is formed on the glass substrate 53 when the user presses the conductive antiglare film 40 with a finger or a pen. 52. This is a mechanism in which the pressed position is detected by electrically detecting this contact through the electrode at the end. On the transparent conductive thin film 52 of the glass substrate 53, dot-shaped spacers 51 are disposed as necessary. Further, by mounting the touch panel on the liquid crystal display device (LCD) 54, the image display device 50 with a touch panel can be configured.

This specification discloses various modes of technology as described above, and the main technologies are summarized below.

One aspect of the present invention is an antiglare film having an antiglare layer on a base film,
The antiglare film characterized in that the arithmetic average roughness Ra (nm) of the surface of the antiglare layer and the correlation length Ic (μm) defined by the following formula satisfy the following relational expression (1): It is.
Relational expression (1): 0 ≦ Ic ≦ 21−8 × exp ((215−Ra) / 40) −13 × exp ((215−Ra) / 400)
Definition formula: Correlation length Ic = root mean square roughness Rq (μm) / root mean square slope Δq × 2 ^1/2

According to such a configuration, it is possible to provide an antiglare film capable of achieving both improvement in visibility and reduction in moire fringes.

In the antiglare film, the arithmetic average roughness Ra (nm) of the surface of the antiglare layer and the correlation length Ic (μm) preferably satisfy the following relational expression (2).
Relational expression (2): 0 ≦ Ic ≦ 17−6 × exp ((225−Ra) / 40) −11 × exp ((225−Ra) / 400)

According to such a configuration, the generation of moire fringes can be further reduced. Therefore, the problem of moire fringes can be solved more.

In the antiglare film, the arithmetic average roughness Ra of the surface of the antiglare layer is preferably in the range of 350 to 1300 nm.

According to such a configuration, the generation of moire fringes can be further reduced. Therefore, the problem of moire fringes can be solved more.

In the antiglare film, the haze resulting from internal scattering of the antiglare layer is preferably in the range of 0 to 0.5%.

According to such a configuration, visibility can be further improved.

In the antiglare film, the antiglare layer preferably contains an actinic radiation curable resin having a viscosity at 25 ° C. in the range of 20 to 3000 mPa · s.

According to such a configuration, the surface shape of the antiglare layer becomes closer to the desired shape. Therefore, both improvement in visibility and reduction in moire fringes can be achieved.

In the antiglare film, it is preferable that the antiglare layer contains fine particles and does not substantially contain a resin that is incompatible with the fine particles and the actinic radiation curable resin.

According to such a configuration, visibility can be further improved.

In the antiglare film, it is preferable that the surface of the antiglare layer has an irregular protrusion shape having no period in the longitudinal direction.

According to such a configuration, visibility can be further improved.

Another aspect of the present invention is a method for producing an antiglare film for producing the antiglare film, wherein the viscosity at 25 ° C. is in the range of 20 to 3000 mPa · s. And an antiglare layer coating composition containing at least one solvent selected from the group consisting of esters, glycol ethers, and alcohols, a coating step of coating on a base film, and a decreasing rate drying section Maintaining the temperature within a range of 90 to 160 ° C., drying the antiglare layer coating composition, and curing the dried antiglare layer coating composition to prevent the antiglare layer coating on the base film. It is a manufacturing method of the anti-glare film characterized by including the hardening process which forms a glare layer.

According to such a configuration, it is possible to provide a method for producing an antiglare film that can achieve both improvement in visibility and reduction in moire fringes.

Further, another aspect of the present invention is a polarizing plate characterized in that the antiglare film is provided.

According to such a configuration, a polarizing plate that achieves both improved visibility and reduced moire fringes can be obtained.

Further, another aspect of the present invention is an image display device including the antiglare film.

According to such a configuration, an image forming apparatus that achieves both improved visibility and reduced moire fringes can be obtained.

Moreover, another aspect of the present invention is a member for a touch panel, characterized in that the antiglare film is provided.

According to such a configuration, a touch panel member that achieves both improved visibility and reduced moire fringes can be obtained. When a touch panel liquid crystal display device or the like is manufactured using such a touch panel member, a touch panel liquid crystal display device that achieves both improved visibility and reduced moire fringes can be obtained.

Hereinafter, the present invention will be specifically described with reference to examples, but the present invention is not limited thereto.

Example 1
<Preparation of base film 1>
(Preparation of silicon dioxide dispersion)
Aerosil R812 (manufactured by Nippon Aerosil Co., Ltd., average particle diameter of 7 nm)
10 parts by mass Ethanol 90 parts by mass The above was stirred and mixed with a dissolver for 30 minutes, and then dispersed with Manton Gorin. 88 parts by mass of methylene chloride was added to the silicon dioxide dispersion while stirring, and the mixture was stirred and mixed for 30 minutes with a dissolver to prepare a silicon dioxide dispersion dilution. The mixture was filtered with a fine particle dispersion dilution filter (Advantech Toyo Co., Ltd .: polypropylene wind cartridge filter TCW-PPS-1N).

<Preparation of base film 1>
(Dope composition)
90 parts by mass of cellulose triacetate (Mn = 148000, Mw = 310000 acetyl group substitution degree 2.92)
Aromatic terminal ester plasticizer (2-4) 10 parts by weight Tinuvin 900 (manufactured by BASF Japan Ltd.) 2.5 parts by weight Silicon dioxide dispersion dilution 4 parts by weight Methylene chloride 432 parts by weight Ethanol 38 parts by weight The solution was put into a container, heated, stirred and completely dissolved, and Azumi Filter Paper No. No. 24 was used for filtration to prepare a dope solution.

Next, the belt was cast evenly on a stainless steel band support using a belt casting apparatus. With the stainless steel band support, the solvent was evaporated until the residual solvent amount reached 100%, and the stainless steel band support was peeled off. The cellulose ester film web was evaporated at 35 ° C., slit to 1.65 m width, and stretched 1.3 times in the TD direction (film width direction) with a tenter, and the MD direction draw ratio was 1.01 times. While stretching, the film was dried at a drying temperature of 160 ° C. The residual solvent amount at the start of drying was 20%. Then, after drying for 15 minutes while transporting the inside of a drying device at 120 ° C. with a number of rolls, slitting to a width of 1.49 m, applying a knurling process with a width of 15 mm and a height of 10 μm at both ends of the film, and winding it around a winding core The base film 1 was obtained. The residual solvent amount of the base film was 0.2%, the film thickness was 40 μm, and the number of turns was 3900 m.

<Preparation of antiglare film 1>
The following anti-glare layer coating composition 1 filtered through a polypropylene filter having a pore diameter of 0.4 μm is applied on the base film 1 produced above using an extrusion coater, and a constant rate drying zone temperature of 80 ° C. is reduced at a reduced rate. After drying at a section temperature of 97 ° C., while purging with nitrogen so that the oxygen concentration becomes 1.0% by volume or less, the illuminance of the irradiated part is 100 mW / cm ² using an ultraviolet lamp and the irradiation amount is 0.25 J / The coating layer was cured as cm ² to form an antiglare layer having a dry film thickness of 8 μm.

After forming the antiglare layer, it was wound up into a roll to produce an antiglare film 1. As a result of observing the surface of the antiglare layer of the antiglare film 1 with an optical interference type surface roughness meter (New View 5030 manufactured by Zygo), irregular projection shapes irregularly in the longitudinal direction and the width direction as shown in FIG. It was found that they are arranged in

[Anti-Glare Layer Coating Composition 1]
The following antiglare layer coating composition 1 was stirred and mixed with a disper to obtain an antiglare layer coating composition 1.
(Actinic radiation curable resin)
Pentaerythritol tri / tetraacrylate (PETA)
(NK ester A-TMM-3L, manufactured by Shin-Nakamura Chemical Co., Ltd.)
100 parts by mass (photopolymerization initiator)
Irgacure 184 (BASF Japan) 5 parts by mass (leveling agent)
Polyether-modified silicone (KF-889, manufactured by Shin-Etsu Chemical Co., Ltd.)
2 parts by mass (solvent)
100 parts by mass of propylene glycol monomethyl ether (PGME)

When only the actinic radiation curable resin of the antiglare layer coating composition 1 was stirred and mixed with a disper and measured using a B-type viscometer at 25 ° C., the resin viscosity was 550 mPa · s. It was.

<Preparation of antiglare film 2>
In the production of the antiglare film 1, an antiglare film 2 was produced in the same manner except that the antiglare layer coating composition 1 was changed to the following antiglare layer coating composition 2.

[Anti-Glare Layer Coating Composition 2]
(Actinic radiation curable resin)
Pentaerythritol tri / tetraacrylate (PETA)
(NK ester A-TMM-3L, manufactured by Shin-Nakamura Chemical Co., Ltd.)
100 parts by mass (photopolymerization initiator)
Irgacure 184 (BASF Japan) 5 parts by mass (leveling agent)
Polyether-modified silicone (KF-889, manufactured by Shin-Etsu Chemical Co., Ltd.)
2 parts by mass (solvent)
Propylene glycol monomethyl ether (PGME) 60 parts by weight Methyl ethyl ketone (MEK) 40 parts by weight

<Preparation of antiglare film 3>
In the production of the antiglare film 1, the antiglare layer coating composition 1 was changed to the following antiglare layer coating composition 3, and the temperature in the decreasing rate drying section in the drying step was changed to 100 ° C. in the same manner. A dazzling film 3 was produced.

[Anti-glare layer coating composition 3]
(Actinic radiation curable resin)
Pentaerythritol tri / tetraacrylate (PETA)
(NK ester A-TMM-3L, manufactured by Shin-Nakamura Chemical Co., Ltd.)
100 parts by mass (photopolymerization initiator)
Irgacure 184 (BASF Japan) 5 parts by mass (leveling agent)
Polyether-modified silicone (KF-889, manufactured by Shin-Etsu Chemical Co., Ltd.)
2 parts by mass (solvent)
100 parts by mass of methyl alcohol (MeOH)

<Preparation of antiglare film 4>
In the production of the antiglare film 1, an antiglare film 4 was produced in the same manner except that the antiglare layer coating composition 1 was changed to the following antiglare layer coating composition 4.

[Anti-Glare Layer Coating Composition 4]
(Actinic radiation curable resin)
Pentaerythritol tri / tetraacrylate (PETA)
(NK ester A-TMM-3L, manufactured by Shin-Nakamura Chemical Co., Ltd.) 90 parts by mass t-butyl acrylate (TBA, manufactured by Osaka Organic Chemical Industry Co., Ltd.)
10 parts by mass (photopolymerization initiator)
Irgacure 184 (BASF Japan) 5 parts by mass (leveling agent)
Polyether-modified silicone (KF-889, manufactured by Shin-Etsu Chemical Co., Ltd.)
2 parts by mass (solvent)
100 parts by mass of propylene glycol monomethyl ether (PGME)

<Preparation of antiglare film 5>
In the production of the antiglare film 1, the antiglare layer coating composition 1 was changed to the following antiglare layer coating composition 5 and the temperature in the decreasing rate drying section in the drying step was changed to 95 ° C. in the same manner. A dazzling film 5 was produced.

[Anti-Glare Layer Coating Composition 5]
(Actinic radiation curable resin)
Pentaerythritol tri / tetraacrylate (PETA)
(NK ester A-TMM-3L, manufactured by Shin-Nakamura Chemical Co., Ltd.) 80 parts by mass 4-hydroxybutyl acrylate (4HBA, manufactured by Osaka Organic Chemical Co., Ltd.) 20 parts by mass (photopolymerization initiator)
Irgacure 184 (BASF Japan) 5 parts by mass (leveling agent)
Polyether-modified silicone (KF-889, manufactured by Shin-Etsu Chemical Co., Ltd.)
2 parts by mass (solvent)
100 parts by mass of methyl alcohol (MeOH)

<Preparation of antiglare film 6>
In the production of the anti-glare film 1, the anti-glare layer coating composition 1 was changed to the following anti-glare layer coating composition 6 and the temperature in the decreasing rate drying section in the drying step was changed to 100 ° C. in the same manner. A dazzling film 6 was produced.

[Anti-glare layer coating composition 6]
(Actinic radiation curable resin)
Pentaerythritol tri / tetraacrylate (PETA)
(NK ester A-TMM-3L, manufactured by Shin-Nakamura Chemical Co., Ltd.) 90 parts by mass Hydroxyethyl acrylate (HEA, manufactured by Osaka Organic Chemical Industry Co., Ltd.) 10 parts by mass (photopolymerization initiator)
Irgacure 184 (BASF Japan) 5 parts by mass (leveling agent)
Polyether-modified silicone (KF-889, manufactured by Shin-Etsu Chemical Co., Ltd.)
2 parts by mass (solvent)
100 parts by mass of propylene glycol monomethyl ether (PGME)

<Preparation of antiglare film 7>
In the production of the antiglare film 1, the antiglare layer coating composition 1 is changed to the antiglare layer coating composition 2 and the temperature of the decreasing rate drying section in the drying step is changed to 87 ° C. in the same manner. Film 7 was produced.

<Preparation of antiglare film 8>
In the production of the antiglare film 1, an antiglare film 7 was produced in the same manner except that the temperature of the decreasing rate drying section in the drying step was changed to 88 ° C.

<Preparation of antiglare film 9>
In the production of the anti-glare film 1, the anti-glare layer coating composition 1 was changed to the following anti-glare layer coating composition 7 and the temperature of the rate-of-decreasing drying section in the drying process was changed to 80 ° C. in the same manner. A dazzling film 9 was produced.

[Anti-Glare Layer Coating Composition 7]
(Actinic radiation curable resin)
80 parts by mass of dipentaerythritol penta / hexaacrylate (NK ester A-DPH, manufactured by Shin-Nakamura Chemical Co., Ltd.)
20 parts by mass of isostearyl acrylate (ISTA) (manufactured by Osaka Organic Chemical Industry Co., Ltd.)
(Photopolymerization initiator)
Irgacure 184 (BASF Japan) 5 parts by mass (leveling agent)
Polyether-modified silicone (KF-889, manufactured by Shin-Etsu Chemical Co., Ltd.)
2 parts by mass (solvent)
Propylene glycol monomethyl ether (PGME) 60 parts by weight Methyl ethyl ketone (MEK) 40 parts by weight

<Preparation of antiglare film 10>
In the production of the antiglare film 1, the antiglare layer coating composition 1 was changed to the following antiglare layer coating composition 8 and the temperature in the decreasing rate drying section in the drying step was changed to 80 ° C. in the same manner. A dazzling film 10 was produced.

[Anti-Glare Layer Coating Composition 8]
(Actinic radiation curable resin)
Lucifral NAG (manufactured by Nippon Paint Co., Ltd.) 100 parts by mass

<Preparation of antiglare film 11>
In the preparation of the antiglare film 1, the antiglare layer coating composition 1 was changed to the antiglare layer coating composition 9 prepared with reference to Example 1 of JP-A-2008-225195, and the drying temperature was further specified. An antiglare film 11 was produced in the same manner as the antiglare film 1 except that the temperature was set at 70 ° C., which was the same as that in Example 1 of Kaikai 2008-225195.

[Anti-Glare Layer Coating Composition 9]
The following antiglare layer coating composition 9 was stirred and mixed with a disper to obtain an antiglare layer coating composition 9.

(Actinic radiation curable resin)
Cyclomer P (ACA) 320
(Unsaturated group-containing acrylic resin mixture, manufactured by Daicel Chemical Industries, Ltd.)
47 parts by mass Dipentaerythritol hexaacrylate (DPHA, manufactured by Daicel Cytec Co., Ltd.) 53 parts by mass (incompatible resin)
Polymethyl methacrylate (weight average molecular weight 480000; manufactured by Mitsubishi Rayon Co., Ltd., BR88)
7.5 parts by mass (photopolymerization initiator)
Irgacure 184 (manufactured by BASF Japan Ltd.) 4.2 parts by mass (solvent)
Methyl ethyl ketone (MEK) 0.84 parts by mass Butanol 45 parts by mass Propylene glycol monomethyl ether (PGME) 7.4 parts by mass

<< Measurement of haze and arithmetic mean roughness Ra, etc. >>
The antiglare films 1 to 11 produced above were subjected to haze measurement to determine the internal haze (Hi). In addition, arithmetic average roughness Ra and the like were also measured under the following conditions.

The results are shown in Table 1 for the obtained internal haze (Hi), arithmetic average roughness Ra, and the like.

《Internal haze (Hi)》
A few drops of silicone oil were dropped on the front and back surfaces of each antiglare film. Next, the antiglare film to which silicone oil was dropped was sandwiched from two sides by two 1 mm thick glass plates (micro slide glass product number S9111, manufactured by MATSUNAMI), and two antiglare properties were obtained. The film was optically adhered. The haze (Ha) of the sample which was optically adhered and the surface haze was removed was measured using a measuring machine (NDH2000) manufactured by Nippon Denshoku Industries Co., Ltd.

Next, glass haze (Hb) was measured by sandwiching only silicone oil between two glass plates. Hb was subtracted from Ha, and the internal haze (Hi) of the antiglare film was calculated.

<< Measurement of arithmetic average roughness Ra, etc. >>
The arithmetic average roughness Ra of the antiglare layer of each antiglare film was measured 10 times using an optical interference type surface roughness meter (New View 5030 manufactured by Zygo), and each antiglare property was determined from the average of the measurement results. The arithmetic average roughness Ra of the film was determined.

The root mean square roughness (Rq) and root mean square slope (Δq) were determined as described above. The correlation length was calculated based on the definition formula.

<Preparation of polarizing plate>
Each anti-glare film 1 to 11 after the durability test, the following polarizer, and the optical film 1 prepared by the following procedure on the back side are bonded to each other with a roll-to-roll so that the longitudinal direction is aligned. did. A schematic diagram of the polarizing plate is shown in FIG.

(Preparation of optical film 1)
<Fine particle dispersion 1>
Fine particles (Aerosil R972V manufactured by Nippon Aerosil Co., Ltd.)
11 parts by mass Ethanol 89 parts by mass The above was stirred and mixed with a dissolver for 50 minutes, and then dispersed with Manton Gorin.

<Fine particle addition liquid 1>
The fine particle dispersion 1 was slowly added to the dissolution tank containing methylene chloride with sufficient stirring. Further, the particles were dispersed by an attritor so that the secondary particles had a predetermined particle size. This was filtered through Finemet NF manufactured by Nippon Seisen Co., Ltd. to prepare a fine particle additive solution 1.
99 parts by mass of methylene chloride 5 parts by mass of fine particle dispersion 1

A main dope solution having the following composition was prepared. First, methylene chloride and ethanol were added to the pressure dissolution tank. Cellulose acetate was added to a pressure dissolution tank containing a solvent while stirring. This is completely dissolved with heating and stirring. This was designated as Azumi Filter Paper No. The main dope solution was prepared by filtration using 244.

<Composition of main dope solution>
Methylene chloride 340 parts by mass Ethanol 64 parts by mass Cellulose acetate with an acetyl group substitution degree of 2.4 (Mn 80000)
100 parts by mass Sugar ester compound (1-23) 10 parts by mass Aromatic terminal ester plasticizer (2-23) 2.5 parts by mass UV absorber (Tinuvin 928 (manufactured by BASF Japan Ltd.))
2.3 parts by mass Particulate additive liquid 1 1.0 part by mass

The above composition was put into a sealed container and dissolved with stirring to prepare a dope solution. Next, an endless belt casting apparatus was used to uniformly cast the dope solution on a stainless steel belt support at a temperature of 33 ° C. and a width of 2000 mm. The temperature of the stainless steel belt was controlled at 30 ° C.

On the stainless steel belt support, the solvent was evaporated until the amount of residual solvent in the cast (cast) film reached 75%, and then peeled off from the stainless steel belt support with a peeling tension of 130 N / m.

Thereafter, the film is stretched 1.4 times in the width direction by a tenter set at 170 ° C., then dried by being transported in a drying zone set at 130 ° C. for 30 minutes, trimmed at both ends, The optical film 1 having a film thickness of 40 μm having a knurling of 1 cm width and 6 μm height was prepared, and wound up with a width of 1.49 m and 3900 m. The in-plane retardation value Ro of the optical film 1 was 50 nm, and the thickness direction retardation Rt was 130 nm.

<Preparation of polarizing plate>
A 120 μm-thick polyvinyl alcohol film was uniaxially stretched (temperature: 110 ° C., stretch ratio: 5 times). This was immersed in an aqueous solution composed of 0.075 g of iodine, 5 g of potassium iodide and 100 g of water for 60 seconds, and then immersed in an aqueous solution of 68 ° C. composed of 6 g of potassium iodide, 7.5 g of boric acid and 100 g of water. This was washed with water and dried to obtain a polarizer. Then, according to the following steps 1 to 5, the polarizer, the anti-glare films 1 to 11 and the optical film 1 are aligned in the longitudinal direction on the back side, and bonded to each other by roll-to-roll. In step 6, the adhesive layer was bonded to each of the polarizing plates 1 to 11.
Step 1: An anti-glare film 1 to 11 and an optical film 1 that are immersed in a 2 mol / L sodium hydroxide solution at 60 ° C. for 90 seconds, then washed with water and dried to saponify the side to be bonded to a polarizer. Obtained.
Step 2: The polarizer was immersed in a polyvinyl alcohol adhesive tank having a solid content of 2% by mass for 1 to 2 seconds.
Step 3: Excess adhesive adhered to the polarizer in Step 2 was gently wiped off, and the antiglare films 1 to 11 treated in Step 1 and the optical film 1 were placed on the back side.
Step 4: The films laminated in Step 3 were bonded at a pressure of 20 to 30 N / cm 2 and a conveyance speed of about 2 m / min.
Step 5: A sample obtained by bonding the polarizer prepared in Step 4 to each of the antiglare films 1 to 11 and the optical film 1 in a drier at 80 ° C. is dried for 2 minutes, wound into a roll, and polarizing plate 1 to 11 were produced.
Step 6: A commercially available acrylic pressure-sensitive adhesive is applied to the optical film 1 of each polarizing plate produced in Step 5 so that the thickness after drying is 25 μm, and is dried in an oven at 110 ° C. for 5 minutes. And a peelable protective film was attached to the adhesive layer. The polarized light was cut (punched) to produce polarizing plates 1 to 11.

<Production of liquid crystal display device>
The polarizing plate on the front side of the panel, which had been previously bonded to the SONY 32-inch display BRAVIA KDL-32EX, was peeled off, and the adhesive layers of the respective polarizing plates 1 to 11 were bonded to the front surface of the glass surface of the liquid crystal cell. . At that time, the direction of bonding of the polarizing plate is such that the surface of the antiglare layer of the antiglare film is on the viewing side, and the absorption axis is in the same direction as the previously bonded polarizing plate. Thus, liquid crystal display devices 1 to 11 were produced.

<Evaluation of liquid crystal display device>
(Visibility evaluation)
Each of the produced liquid crystal display devices 1 to 11 was allowed to stand at 80 ° C. for 250 hours and then returned to 23 ° C. and 55% RH to evaluate the visibility. Sensory evaluation of image visibility was performed by 30 evaluators, and the average score was obtained. Ten points are the best, there are few reflections, and sharpness is also high. One point is the worst. Seven or more points are acceptable levels.

Table 1 summarizes the measurement results such as the haze and arithmetic average roughness Ra of the antiglare films 1 to 11 and the visibility evaluation results of the liquid crystal display devices 1 to 11.

As is apparent from the results shown in Table 1, the antiglare layer does not substantially contain a resin that is incompatible with the fine particles or the actinic radiation curable resin, and the arithmetic average roughness of the surface of the antiglare layer A polarizing plate produced using the antiglare film according to the present embodiment in which the thickness (Ra) and the correlation length satisfy the relational expression (1), and the internal haze of the antiglare layer is 0 to 1.0% It can be seen that the use of the liquid crystal display device is excellent in visibility.

Among them, the antiglare film according to this embodiment having an arithmetic average roughness Ra of 350 to 1300 nm is particularly excellent in visibility when used in a liquid crystal display device.

An antiglare layer coating composition obtained by diluting an actinic radiation curable resin having a viscosity at 25 ° C. in the range of 20 to 3000 mPa · s with glycol ethers such as PGME and EPGE, or alcohols such as ethanol and methanol, at least The arithmetic average roughness Ra and the internal haze of the antiglare layer are formed through the drying process and the curing process, and are processed under the condition that the drying rate of the drying process is maintained at 90 to 160 ° C. Can be easily controlled within the scope of the present invention, and the object and effects of the present invention can be obtained well.

Further, it can be seen that the antiglare film of the present invention in which the internal haze of the antiglare layer is 0 to 0.5% is preferable because the objective effect of the present invention can be obtained satisfactorily.

About the anti-glare film which concerns on this embodiment, as a result of observing the anti-glare layer surface with the optical interference type surface roughness meter (New View 5030 by Zygo), irregular protrusion shape like the anti-glare film 1 is shown. It was irregularly arranged in the longitudinal direction and the width direction.

Further, for the antiglare films 1 to 11, an antiglare layer is formed with a pencil of each hardness using a 500 g weight according to a pencil hardness evaluation method specified by JIS-K5400 using a test pencil specified by JIS-S6006. As a result of scratching the surface 5 times and evaluating the pencil hardness, all of the antiglare films according to the present embodiment were 3H or more, and had good hard coat properties.

Example 2
<Preparation of clear hard coat film 1>
The following clear hard coat coating composition 1 filtered through a polypropylene filter having a pore diameter of 0.4 μm was coated on the base film 1 prepared in Example 1 using a micro gravure coater, and a constant rate drying section temperature of 80 ° C., After drying at a reduced rate drying section temperature of 80 ° C., while purging with nitrogen so that the atmosphere has an oxygen concentration of 1.0% by volume or less, the illuminance of the irradiated part is 100 mW / cm ² using an ultraviolet lamp and the irradiation amount is 0 The coating layer was cured at .25 J / cm ² to form a clear hard coat layer having a dry film thickness of 5 μm.

After forming the clear hard coat layer, it was wound up into a roll to produce a clear hard coat film 1. As a result of measuring the total haze of the clear hard coat film 1 using a measuring machine (NDH2000) manufactured by Nippon Denshoku Industries Co., Ltd., it was 0.3% and was very excellent in clearness.

[Clear hard coat layer coating composition 1]
The following clear hard coat layer coating composition 1 was stirred and mixed with a disper to obtain a clear hard coat layer coating composition 1.

(Actinic radiation curable resin)
100 parts by mass of dipentaerythritol polyacrylate (NK ester A-9550, manufactured by Shin-Nakamura Chemical Co., Ltd.)
(Photopolymerization initiator)
Irgacure 184 (BASF Japan) 5 parts by mass (leveling agent)
Acrylic copolymer (BYK-350, manufactured by Big Chemie Japan)
2 parts by mass (solvent)
Propylene glycol monomethyl ether (PGME) 10 parts by weight Methyl ethyl ketone 45 parts by weight Methyl acetate 45 parts by weight

<Preparation of polarizing plate>
The clear hard coat film 1, the following polarizer, and the optical film 1 produced in Example 1 on the back side were bonded together with a roll-to-roll so that the longitudinal direction was matched, and the polarizing plate 100 was produced.

<Preparation of polarizing plate>
A 120 μm-thick polyvinyl alcohol film was uniaxially stretched (temperature: 110 ° C., stretch ratio: 5 times). This was immersed in an aqueous solution composed of 0.075 g of iodine, 5 g of potassium iodide and 100 g of water for 60 seconds, and then immersed in an aqueous solution of 68 ° C. composed of 6 g of potassium iodide, 7.5 g of boric acid and 100 g of water. This was washed with water and dried to obtain a polarizer. Next, in accordance with Steps 1 to 5, the polarizer, the clear hard coat film 1 and the optical film 1 are aligned with the back surface side in the longitudinal direction, and bonded together by roll-to-roll to produce a polarizing plate. The adhesive layer was bonded together.
Step 1: Soaked in a 2 mol / L sodium hydroxide solution at 60 ° C. for 90 seconds, then washed with water and dried to saponify the side to be bonded to the polarizer to obtain a clear hard coat film 1 and an optical film 1 .
Step 2: The polarizer was immersed in a polyvinyl alcohol adhesive tank having a solid content of 2% by mass for 1 to 2 seconds.
Step 3: Excess adhesive adhered to the polarizer in Step 2 was lightly wiped off, and the optical film 1 was placed on the clear hard coat film 1 treated in Step 1 and the back side.
Step 4: The films laminated in Step 3 were bonded at a pressure of 20 to 30 N / cm ² and a conveyance speed of about 2 m / min.
Step 5: A sample obtained by bonding the polarizer, the clear hard coat film 1 and the optical film 1 prepared in Step 4 in a dryer at 80 ° C. is dried for 2 minutes, wound into a roll, and the polarizing plate 100 is produced. did.
Step 6: Apply a commercially available acrylic pressure-sensitive adhesive to the protective film of the polarizing plate prepared in Step 5 so that the thickness after drying is 25 μm, and dry in an oven at 110 ° C. for 5 minutes to form an adhesive layer. A peelable protective film was attached to the adhesive layer. This polarized light was cut (punched) to produce a polarizing plate 100.

<Production of Liquid Crystal Display Device 101>
As shown in FIG. 5, the polarizing plate 1 produced in Example 1 was peeled off the peelable protective film of the pressure-sensitive adhesive layer, and was bonded to the rear side through the glass of the liquid crystal cell. Furthermore, the peelable protective film of the pressure-sensitive adhesive layer of the polarizing plate 100 produced above is peeled off and bonded to the front side to produce a liquid crystal panel 101. The liquid crystal panel 101 is attached to a panel made of SONY notebook PC VAIO TYPE B. The liquid crystal display device 101 was manufactured by removing and fitting.

<Production of liquid crystal display devices 102 to 111>
Liquid crystal display devices 102 to 111 were manufactured in the same manner except that the polarizing plate 1 on the rear side was changed to polarizing plates 2 to 11 in the manufacture of the liquid crystal display device 101.

The manufactured liquid crystal display devices 101 to 111 were observed for moire fringes and evaluated according to the following criteria.

<< Evaluation of display device >>
(Moire fringe evaluation)
XX: Generation of moire fringes can be clearly confirmed.
X: Presence of moiré fringes can be confirmed. A practically problematic level.
(Triangle | delta): Although it is dim, presence of a moire fringe can be confirmed easily.
○: The presence of moiré fringes can be confirmed slightly by gazing.
A: The presence of moiré fringes cannot be confirmed at all.

The evaluation results are shown in Table 2.

As is clear from the results shown in Table 2, the liquid crystal display device used on the rear side using the polarizing plate composed of the antiglare film according to the present embodiment has no moiré fringes observed. It can be seen that it is excellent in preventing occurrence.

Example 3
<Preparation of antiglare film 1 with conductive film>
In the production of the antiglare film 1, a double-sided antiglare film 1 was produced in the same manner except that the antiglare layer coating layer composition 1 was coated on both sides.

Next, a transparent conductive thin film of indium tin oxide (ITO) having a surface resistivity of about 200Ω is provided on one side of the antiglare layer using a sputtering method, and the antiglare film 1 with a conductive film shown in FIG. Was made.

<Preparation of antiglare films 2 to 11 with conductive film>
In the production of the antiglare films 2 to 11, double-sided antiglare films 2 to 11 were produced in the same manner as the double-sided antiglare film 1, except that an antiglare layer was coated on both sides.

Next, in the same manner as the production of the antiglare film 1 with a conductive film, after providing an antiglare layer on both sides, a transparent conductive thin film of ITO having a surface resistivity of about 200Ω on one side of the antiglare layer, The antiglare films 2 to 11 with a conductive film were prepared by using a sputtering method.

<Preparation of Resistive Touch Panel Liquid Crystal Display 201>
A film with a conductive film of a commercially available resistive film type touch panel liquid crystal display device (model name: LCD-USB10XB-T, manufactured by IO DATA Co.) is peeled off, and the antiglare film 1 with the conductive film produced above is shown in FIG. Thus, a resistive film type touch panel liquid crystal display device 201 was produced.

<Preparation of resistive touch panel liquid crystal display devices 202-211>
The resistive film type touch panel liquid crystal display device 202 is manufactured in the same manner except that the antiglare film 1 with conductive film is changed to the antiglare films 2 to 11 with conductive film in the production of the resistive film type touch panel liquid crystal display device 1. 211 was produced.

<< Evaluation of display device >>
In the same manner as in Example 1, the visibility of the resistive touch panel liquid crystal display devices 201 to 211 was evaluated.

(Visibility evaluation)
The produced resistive film type touch panel liquid crystal display devices 201 to 211 were allowed to stand at 80 ° C. for 250 hours and then returned to 23 ° C. and 55% RH to evaluate the visibility.

The sensory evaluation of image visibility was performed by 30 evaluators, and the average score was obtained. Ten points are the best, there are few reflections, and sharpness is also high. One point is the worst. Seven or more points are acceptable levels.

<Film evaluation>
(Pen sliding resistance)
The antiglare films 1 to 11 with conductive film were evaluated for pen sliding resistance under the following conditions. The results obtained are shown in Table 4.

The anti-glare layer of each anti-glare film with a conductive film used in a resistive touch panel liquid crystal display device is a polyacetal pen with a tip of 0.08 mmφ, with a load of 500 g and a pen sliding speed of 100 mm / sec. The straight line 40 mm was reciprocated 150,000 times, and the anti-glare layer was scratched and peeled after the reciprocation.

The evaluation results are shown in Table 3.

As is clear from the results shown in Table 3, the antiglare film with a conductive film according to the present embodiment and the resistive film type touch panel liquid crystal display device using the film have improved visibility and pen sliding resistance. It turns out that it is excellent.

ADVANTAGE OF THE INVENTION According to this invention, the anti-glare film which can achieve coexistence of a visibility improvement and the reduction of a moire fringe, and its manufacturing method are provided. Moreover, the polarizing plate provided with the said anti-glare film, an image display apparatus, and the member for touchscreens are provided.

Claims (11)

1. An antiglare film having an antiglare layer on a base film,
   The antiglare film characterized in that the arithmetic average roughness Ra (nm) of the surface of the antiglare layer and the correlation length Ic (μm) defined by the following formula satisfy the following relational expression (1): .
   Relational expression (1): 0 ≦ Ic ≦ 21−8 × exp ((215−Ra) / 40) −13 × exp ((215−Ra) / 400)
   Definition formula: Correlation length Ic = root mean square roughness Rq (μm) / root mean square slope Δq × 2 ^1/2
2. The antiglare film according to claim 1, wherein the arithmetic average roughness Ra (nm) of the surface of the antiglare layer and the correlation length Ic (µm) satisfy the following relational expression (2). .
   Relational expression (2): 0 ≦ Ic ≦ 17−6 × exp ((225−Ra) / 40) −11 × exp ((225−Ra) / 400)
3. The antiglare film according to claim 1 or 2, wherein the arithmetic average roughness Ra of the surface of the antiglare layer is in the range of 350 to 1300 nm.
4. The antiglare film according to any one of claims 1 to 3, wherein haze caused by internal scattering of the antiglare layer is in the range of 0 to 0.5%.
5. The antiglare layer contains an actinic radiation curable resin having a viscosity within a range of 20 to 3000 mPa · s at 25 ° C. The antiglare film as described.
6. 6. The antiglare property according to claim 5, wherein the antiglare layer contains fine particles and does not substantially contain a resin that is incompatible with the fine particles and the actinic radiation curable resin. the film.
7. The antiglare film according to any one of claims 1 to 6, wherein a surface of the antiglare layer has an irregular protrusion shape having no period in the longitudinal direction. .
8. An antiglare film manufacturing method for manufacturing the antiglare film according to any one of claims 1 to 7,
   Application of an antiglare layer comprising an actinic radiation curable resin having a viscosity at 25 ° C. in the range of 20 to 3000 mPa · s and at least one solvent selected from the group consisting of esters, glycol ethers, and alcohols An application step of applying the composition onto a substrate film;
   A drying step of drying the antiglare layer coating composition while maintaining the temperature of the reduced rate drying section within a range of 90 to 160 ° C .;
   A method for producing an antiglare film, comprising: curing the dried antiglare layer coating composition to form an antiglare layer on the substrate film.
9. A polarizing plate comprising the antiglare film according to any one of claims 1 to 7.
10. An image display device comprising the antiglare film according to any one of claims 1 to 7.
11. A touch panel member comprising the antiglare film according to any one of claims 1 to 7.

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