CN113661418A

CN113661418A - Anti-glare film, method for producing anti-glare film, optical member, and image display device

Info

Publication number: CN113661418A
Application number: CN202080027544.0A
Authority: CN
Inventors: 平冈慎哉; 桥本尚树
Original assignee: Nitto Denko Corp
Current assignee: Nitto Denko Corp
Priority date: 2019-04-10
Filing date: 2020-04-08
Publication date: 2021-11-16
Anticipated expiration: 2040-04-08
Also published as: CN113661418B; JP7393875B2; WO2020209288A1; TW202040166A; JP2020173340A; KR20210149719A; JP2022183161A; SG11202111128WA

Abstract

Provided is an anti-glare film which can suppress reflection glare. An anti-glare film (10) comprising a light-transmitting substrate (A) (11) and an anti-glare layer (B) (12) laminated thereon, wherein the anti-glare film (10) has irregularities formed on the outermost surface thereof on the anti-glare layer (B) (12) side, said irregularities satisfying the following expressions (1) and (2). Ry is not less than 1.7(1) and thetaa is not less than 0.7 (2). in the formula (1), Ry is the maximum height [ mu ] m of the convex part of the concave-convex part, and in the formula (2), thetaa is the average inclination angle [ ° ] of the concave-convex part.

Description

Anti-glare film, method for producing anti-glare film, optical member, and image display device

Technical Field

The present invention relates to an antiglare film, a method for producing an antiglare film, an optical member, and an image display device.

Background

In various image display devices such as cathode ray tube display devices (CRTs), liquid crystal display devices (LCDs), Plasma Display Panels (PDPs), and electroluminescence displays (ELDs), anti-glare (anti-glare) treatment is performed to prevent a decrease in contrast caused by reflection of external light such as fluorescent light or sunlight and reflection glare (reflected glare) of images on the surface of the image display devices.

There are many documents describing an antiglare film, and for example, patent documents 1 and 2 are available.

Documents of the prior art

Patent document

Patent document 1 Japanese patent laid-open publication No. 2009-109683

Patent document 2 Japanese patent laid-open No. 2003-202416

Disclosure of Invention

Problems to be solved by the invention

From the viewpoint of visibility, the antiglare film is required to suppress reflection glare caused by reflection of external light.

For example, there has been an increasing demand for Public Information Displays (PIDs) in recent years. PIDs are also often used outdoors. When a display (image display device) is used outdoors, reflection glare caused by reflection of external light is more likely to occur than when the display is used indoors. When the reflected glare occurs, the image may be difficult to visually recognize.

Accordingly, an object of the present invention is to provide an antiglare film capable of suppressing reflection glare, a method for producing the antiglare film, an optical member, and an image display device.

Means for solving the problems

In order to achieve the above object, the present invention provides an antiglare film comprising a light-transmitting substrate (A) and an antiglare layer (B) laminated thereon,

wherein the antiglare film has unevenness formed on the outermost surface thereof on the antiglare layer (B) side,

the unevenness satisfies the following expressions (1) and (2).

Ry≥1.7 (1)

θa≥0.7 (2)

In the above formula (1), Ry is the maximum height [ μm ] of the convex portion of the unevenness,

in the above formula (2), θ a is an average inclination angle [ ° ] of the irregularities.

The method for producing an antiglare film of the present invention is characterized by comprising an antiglare layer (B) forming step of forming the antiglare layer (B) on the light-transmitting substrate (a) so as to satisfy the above formulae (1) and (2),

the step of forming the antiglare layer (B) includes: a coating step of coating the light-transmitting substrate (a) with a coating liquid; and a coating film forming step of drying the coating liquid to form a coating film,

the coating liquid contains a resin and a solvent.

The optical member of the present invention is an optical member comprising the antiglare film of the present invention.

The image display device of the present invention is an image display device including the antiglare film of the present invention or the optical member of the present invention.

ADVANTAGEOUS EFFECTS OF INVENTION

According to the present invention, an antiglare film, an optical member, and an image display device in which reflection glare is suppressed can be provided.

Drawings

Fig. 1 is a cross-sectional view showing an example of the antiglare film of the present invention.

Fig. 2 is a cross-sectional view showing another example of the antiglare film of the present invention.

Fig. 3 is a cross-sectional view showing an example of the antiglare film.

Detailed Description

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

In the antiglare film of the present invention, for example, the antiglare layer (B) may contain fine particles.

In the antiglare film of the present invention, for example, in the antiglare layer (B), irregularities are formed on a surface opposite to the light-transmissive substrate (a), and the weight-average particle diameter of the fine particles may be larger than a thickness obtained by subtracting a maximum height of a convex portion of the irregularities from a maximum thickness of the antiglare layer (B).

In the antiglare film of the present invention, for example, the weight average particle diameter of the fine particles may be in the range of 4 to 9 μm.

In the antiglare film of the present invention, for example, another layer may be further laminated on the surface of the antiglare layer (B) opposite to the light-transmitting substrate (a).

The antiglare film of the present invention may be, for example, an antiglare film as follows: the antiglare film is characterized in that an antiglare layer (B) and another layer are sequentially laminated on a light-transmitting substrate (A), and irregularities are formed on the outermost surface of the other layer, wherein the irregularities satisfy the following expressions (1) and (2).

Ry≥1.7 (1)

θa≥0.7 (2)

In the method for producing an antiglare film of the present invention, for example, the step of forming the antiglare layer (B) may further include a curing step of curing the coating film.

In the method for producing an antiglare film of the present invention, for example, the coating liquid may contain fine particles.

The optical member of the present invention may be, for example, a polarizing plate.

The image display device of the present invention may be, for example, a public information display.

[1. antiglare film ]

As described above, the antiglare film of the present invention is characterized in that an antiglare layer (B) is laminated on a light-transmitting substrate (a), and irregularities are formed on the outermost surface of the antiglare film on the antiglare layer (B) side, the irregularities satisfying the following expressions (1) and (2).

Ry≥1.7 (1)

θa≥0.7 (2)

Fig. 1 is a cross-sectional view showing an example of the structure of the antiglare film of the present invention. As shown in the drawing, the antiglare film 10 has an antiglare layer (B)12 laminated on one surface of a light-transmitting substrate (a) 11. The antiglare layer (B)12 contains fine particles 12B and a thixotropy-imparting agent 12c in the resin layer 12 a. The antiglare film 10 has irregularities formed on the outermost surface on the antiglare layer (B)12 side (the surface of the antiglare layer (B)12 on the side opposite to the light-transmitting substrate (a) 11). The maximum height Ry of the convex part of the concave-convex part is more than 1.7 μm. The average inclination angle θ a (not shown) of the irregularities is 0.7 ° or more. The particle diameter D of the fine particles 12B is larger than the film thickness t obtained by subtracting Ry from the maximum thickness D of the antiglare layer (B). Fig. 1 is an illustration, but the present invention is not limited thereto. For example, the antiglare film of the present invention may or may not contain fine particles and a thixotropy-imparting agent. In fig. 1, the particle diameter D of the fine particles 12B is larger than the film thickness t of the antiglare layer (B), but the present invention is not limited thereto.

Fig. 3 is a cross-sectional view showing an example of the structure of an antiglare film which is not the antiglare film of the present invention. This antiglare film is the same as the antiglare film of fig. 1 except that the maximum height Ry of the irregularities is less than 1.7 μm and the average inclination angle θ a of the irregularities (not shown) is less than 0.7 °.

Fig. 2 is a cross-sectional view showing another example of the structure of the antiglare film of the present invention. As shown in the drawing, in the antiglare film 10, another layer 13 is further laminated on the surface of the antiglare layer (B)12 opposite to the light-transmitting substrate (a) 11. The other layer 13 is not particularly limited, and may be, for example, a low refractive index layer, an antireflection layer, a high refractive index layer, a hard coat layer, an adhesive layer, or the like. Except for this, the configuration of the antiglare film 10 of fig. 2 is the same as that of the antiglare film 10 of fig. 1. In fig. 2, the antiglare film 10 has irregularities formed on the outermost surface on the antiglare layer (B)12 side (the surface of the other layer 13 on the opposite side to the light-transmissive substrate (a) 11). The maximum height Ry of the convex part of the concave-convex part is more than 1.7 μm. The average inclination angle θ a (not shown) of the irregularities is 0.7 ° or more. The maximum height of the portions (the antiglare layer (B)12 and the other layer 13) other than the light-transmitting substrate (a)11 in the antiglare film 10 is represented by d in the figure. In addition, in the antiglare layer (B)12, irregularities are formed on the surface on the opposite side (the other layer 13 side) to the light-transmitting substrate (a) 11. The film thickness obtained by subtracting the maximum height Ry 'of the irregularities of the antiglare layer (B)12 from the maximum thickness d' of the antiglare layer (B)12 is represented by t in the figure. As shown, t is equal to d '-Ry' and is equal to d-Ry. The particle diameter D of the fine particles 12b is larger than the film thickness t as in the case of fig. 1, but the present invention is not limited thereto as described above. As in the case of fig. 1, the antiglare layer (B)12 may or may not contain fine particles and a thixotropy-imparting agent. In fig. 2, the other layer 13 is a single layer, but may be a plurality of layers. When the other layer 13 is not present, as shown in fig. 1, Ry 'is equal to Ry, and d' is equal to d.

The light-transmitting substrate (a), the antiglare layer (B), and the other layer are further described below with reference to examples. In the following description, the case where the antiglare layer (B) is an antiglare hard coat layer will be mainly described, but the present invention is not limited thereto.

The light-transmitting substrate (a) is not particularly limited, and examples thereof include a transparent plastic film substrate. The transparent plastic film substrate is not particularly limited, but is preferably excellent in visible light transmittance (preferably transmittance of 90% or more) and transparency (preferably haze value of 1% or less), and examples thereof include those described in jp 2008-90263 a. As the transparent plastic film substrate, those having less optical birefringence can be suitably used. The antiglare film of the present invention can be used as a protective film for a polarizing plate, and in this case, as the transparent plastic film substrate, a film made of Triacetylcellulose (TAC), polycarbonate, an acrylic polymer, a polyolefin having a cyclic or norbornene structure, or the like is preferable. In the present invention, the transparent plastic film substrate may be a polarizer itself, as described later. With such a configuration, a protective layer made of TAC or the like is not required, and the structure of the polarizing plate can be simplified, so that the number of manufacturing processes of the polarizing plate or the image display device can be reduced, and the production efficiency can be improved. In addition, with such a configuration, the polarizing plate can be further reduced in thickness. When the transparent plastic film substrate is a polarizer, the antiglare layer (B) and the antireflection layer (C) function as protective layers. In addition, with such a configuration, the antiglare film also functions as a cover plate when mounted on, for example, the surface of a liquid crystal cell.

In the present invention, the thickness of the light-transmitting substrate (A) is not particularly limited, but is, for example, in the range of 10 to 500. mu.m, 20 to 300. mu.m, or 30 to 200. mu.m, in view of workability such as strength and handling property, and thin layer property. The refractive index of the light-transmitting substrate (a) is not particularly limited. The refractive index is, for example, in the range of 1.30 to 1.80 or 1.40 to 1.70.

In the antiglare film of the present invention, the resin contained in the light-transmitting substrate (a) may contain an acrylic resin, for example.

In the antiglare film of the present invention, the light-transmitting substrate (a) may be an acrylic film, for example.

In the antiglare film of the present invention, as described above, the outermost surface on the antiglare layer (B) side has irregularities, and the maximum height Ry of the irregularities is 1.7 μm or more. The maximum height Ry may be, for example, 2.0 μm or more or 2.3 μm or more, and may be, for example, 9 μm or less, 8 μm or less, 7 μm or less, or 6 μm or less. The maximum height Ry may be, for example, 1.7 to 9 μm, 1.7 to 8 μm, 2.0 to 7 μm, or 2.3 to 6 μm. In view of suppressing reflection glare, Ry is preferably large, and is preferably not excessively large in view of a haze value described later. In the present invention, the maximum height Ry is a value based on JIS B0601 (1994 version). The method for measuring Ry is not particularly limited, and for example, it can be measured by the measurement method described in the examples described later.

In the antiglare film of the present invention, the "outermost surface on the antiglare layer (B) side" is the outermost surface on the antiglare layer (B) side. Specifically, when the other layer is not present (for example, fig. 1), the "outermost surface on the antiglare layer (B) side" is a surface of the antiglare layer (B) on the opposite side from the light-transmitting substrate (a). When the other layer is present (for example, fig. 2), the "outermost surface on the antiglare layer (B) side" is an outermost surface on the opposite side of the light-transmitting substrate (a) in the other layer.

As described above, the antiglare film of the present invention has an average inclination angle θ a (°) of 0.7 or more in the uneven shape on the outermost surface on the antiglare layer (B) side. The average inclination angle θ a may be, for example, 0.7 ° or more, 0.8 ° or more, 0.9 ° or more, or 1.0 ° or more, or may be 8 ° or less, 7 ° or less, 6 ° or less, or 5 ° or less. The average inclination angle thetaa may be, for example, 0.7 to 8 deg., 0.7 to 7 deg., 0.7 to 6 deg., 0.7 to 5 deg., 0.8 to 8 deg., 0.8 to 7 deg., 0.8 to 6 deg., 0.8 to 5 deg., 0.9 to 8 deg., 0.9 to 7 deg., 0.9 to 6 deg., 0.9 to 5 deg., 1.0 to 8 deg., 1.0 to 7 deg., 1.0 to 6 deg., or 1.0 to 5 deg. From the viewpoint of suppressing reflection glare, θ a is preferably large, and from the viewpoint of a haze value described later, θ a is preferably not excessively large. Here, the average inclination angle θ a is defined by the following equation (3). The average inclination angle θ a can be measured by, for example, a method described in examples described later.

Average tilt angle θ a ═ tan^-1Δa (3)

In the above equation (3), Δ a is a value obtained by dividing the sum (h1+ h2+ h3 · + hn) of the differences (heights h) between the peaks and the valleys adjacent to each other in the reference length L of the roughness curve defined in JIS B0601 (1994 version) by the above reference length L, as shown in the following equation (4). The roughness curve is a curve obtained by removing a surface relief component longer than a predetermined wavelength from a cross-sectional curve by a phase difference compensation type high-pass filter. The cross-sectional curve is a contour which appears in the cut of the target surface when the target surface is cut by a plane perpendicular to the target surface.

Δa＝(h1+h2+h3···+hn)/L (4)

In the antiglare film of the present invention, for example, the haze value may be 4% or more, 6% or more, 10% or more, or 15% or more, for example, 50% or less, 40% or less, 35% or less, or less than 30%. The haze value may be, for example, 4 to 50%, 6 to 40%, 10 to 40%, further 15 to 40%, or 15 to 35%. The haze value is a haze value (opacity) of the entire antiglare film according to JIS K7136 (2000 edition). In general, in the antiglare film, reflection glare is easily suppressed when the haze value is large. However, if the haze value is too large, the display characteristics are likely to be degraded, for example, the image may be blurred, and the contrast may be degraded in a dark place. However, according to the present invention, by making Ry and θ a satisfy the above equations (1) and (2), reflection glare can be suppressed even if the haze value is reduced to, for example, 50% or less, 40% or less, 35% or less, or less than 30%. In order to minimize the haze value, the fine particles and the resin may be selected so that a difference in refractive index between the resin and the fine particles (for example, in a range of 0.001 to 0.02) described later is minimized, in addition to the adjustment of Ry and θ a.

In the antiglare film of the present invention, for example, the antiglare layer (B) may contain a resin and a filler. The filler may include at least one of microparticles and a thixotropy-imparting agent (thixotropic agent).

In the antiglare film of the present invention, for example, the resin contained in the antiglare layer (B) may contain an acrylate resin (also referred to as an acrylic resin).

In the antiglare film of the present invention, for example, the resin contained in the antiglare layer (B) may contain a urethane acrylate resin.

In the antiglare film of the present invention, for example, the resin contained in the antiglare layer (B) may be a copolymer of a curable urethane acrylate resin and a polyfunctional acrylate.

The antiglare film of the present invention may be, for example: the antiglare layer (B) is formed by using an antiglare layer forming material containing a resin and a filler, and the antiglare layer (B) has an aggregate portion forming a convex portion on a surface of the antiglare layer (B) due to aggregation of the filler. In the above-described aggregate portion forming the convex portion, the filler may be present in a state where a plurality of fillers are concentrated in one direction of the planar direction of the antiglare layer (B). In the image display device of the present invention, the antiglare film of the present invention may be arranged such that, for example, one direction in which the plurality of fillers are aggregated coincides with the longitudinal direction of the black matrix pattern.

In the antiglare film of the present invention, the thixotropy-imparting agent may be, for example, at least one selected from the group consisting of an organoclay, an oxidized polyolefin and a modified urea. The thixotropy-imparting agent may be, for example, a thickener.

In the antiglare film of the present invention, the thixotropy-imparting agent may be contained in an amount of, for example, 0.2 to 5 parts by weight based on 100 parts by weight (mass) of the resin in the antiglare layer (B).

In the antiglare film of the present invention, the fine particles may be contained in an amount of, for example, 0.2 to 12 parts by weight or 0.5 to 12 parts by weight based on 100 parts by weight of the resin of the antiglare layer (B).

In the method for producing an antiglare film of the present invention, the surface shape of the antiglare film may be adjusted by further adjusting the weight part of the fine particles relative to 100 parts by weight of the resin in the antiglare layer forming material.

The antiglare layer (B) can be formed, for example, as follows: the coating liquid is formed by applying a coating liquid containing the resin, the filler and a solvent to at least one surface of the light-transmissive substrate (a) to form a coating film, and then removing the solvent from the coating film. Examples of the resin include a thermosetting resin and an ionizing radiation curable resin which is cured by ultraviolet rays and/or light. As the resin, commercially available thermosetting resins, ultraviolet curable resins, and the like can be used.

Examples of the thermosetting resin and the ultraviolet curable resin include curable compounds having at least one group of an acrylate group and a methacrylate group, which are cured by heat, light (ultraviolet rays, etc.) or an electron beam, and examples thereof include oligomers or prepolymers of acrylates, methacrylates, and the like of polyfunctional compounds such as silicone resins, polyester resins, polyether resins, epoxy resins, urethane resins, alkyd resins, spiroacetal resins, polybutadiene resins, polythiol polyene resins, polyhydric alcohols, and the like. These may be used alone or in combination of two or more.

Among the above resins, for example, a reactive diluent having at least one of an acrylate group and a methacrylate group can also be used. As the reactive diluent, for example, those described in Japanese patent application laid-open No. 2008-88309 can be used, and examples thereof include monofunctional acrylates, monofunctional methacrylates, polyfunctional acrylates, and polyfunctional methacrylates. The reactive diluent is preferably an acrylate having 3 or more functions and a methacrylate having 3 or more functions. This is because the antiglare layer (B) can be made excellent in hardness. Examples of the reactive diluent include butanediol glyceryl ether diacrylate, isocyanuric acid acrylate, and isocyanuric acid methacrylate. These may be used alone or in combination of two or more.

The main functions of the fine particles for forming the antiglare layer (B) are to impart antiglare properties by forming a surface of the antiglare layer (B) into a concavo-convex shape, and to control the haze value of the antiglare layer (B). The haze value of the antiglare layer (B) can be designed by controlling the difference in refractive index between the fine particles and the resin. Examples of the fine particles include inorganic fine particles and organic fine particles. The inorganic fine particles are not particularly limited, and examples thereof include silicon oxide particles, titanium oxide particles, aluminum oxide particles, zinc oxide particles, tin oxide particles, calcium carbonate particles, barium sulfate particles, talc particles, kaolin particles, and calcium sulfate particles. The organic fine particles are not particularly limited, and examples thereof include polymethyl methacrylate resin powder (PMMA particles), silicone resin powder, polystyrene resin powder, polycarbonate resin powder, acrylic-styrene resin powder, benzoguanamine resin powder, melamine resin powder, polyolefin resin powder, polyester resin powder, polyamide resin powder, polyimide resin powder, polyvinyl fluoride resin powder, and the like. These inorganic fine particles and organic fine particles may be used alone or in combination of two or more.

The particle diameter (D) (weight average particle diameter) of the fine particles is not particularly limited, and is, for example, in the range of 2 to 10 μm. By setting the weight average particle diameter of the fine particles within the above range, for example, an antiglare film having more excellent antiglare properties and capable of suppressing reflection glare can be obtained. From the viewpoint of suppressing reflection glare from an oblique direction, the weight average particle diameter of the fine particles is preferably not too small. From the viewpoint of suppressing reflection glare from the front direction, the weight average particle diameter of the fine particles is preferably not too large. The weight average particle diameter of the fine particles may be, for example, 4 μm or more, and may be, for example, 9 μm or less or 8 μm or less. The weight average particle diameter of the fine particles may be, for example, 4 to 9 μm or 4 to 8 μm. The weight average particle diameter of the fine particles can be measured by, for example, the coulter counter method. For example, the number and volume of fine particles are measured by measuring the resistance of the electrolyte solution corresponding to the volume of the fine particles when the fine particles pass through the fine pores using a particle size distribution measuring apparatus (trade name: Coulter Multisizer, Beckman Coulter, Inc.) using a micropore resistance method, and the weight average particle diameter is calculated.

The shape of the fine particles is not particularly limited, and for example, the fine particles may be substantially spherical in the form of beads or may be amorphous in the form of powder or the like, and substantially spherical fine particles are preferable, substantially spherical fine particles having an aspect ratio of 1.5 or less are more preferable, and spherical fine particles are most preferable.

The content of the fine particles in the antiglare layer (B) is not particularly limited, and may be appropriately set, for example, in consideration of the surface shape of the antiglare layer (B). The relationship between the content (in parts by weight with respect to the resin) and the weight-average particle diameter of the fine particles and the surface shape of the antiglare layer (B) will be described later.

In the antiglare layer (B), the filler may be fine particles or a thixotropy imparting agent. The thixotropy-imparting agent may be contained alone or in addition to the fine particles. By including the thixotropy-imparting agent, the aggregation state of the fine particles can be easily controlled. Examples of the thixotropy imparting agent include organoclays, oxidized polyolefins, and modified ureas.

The organoclay is preferably an organically treated layered clay in order to improve the affinity with the resin. The organoclay can be prepared by itself or a commercially available product can be used. Examples of the commercially available products include: LUCENTITE SAN, LUCENTITE STN, LUCENTITE SEN, LUCENTITE SPN, SOMASIF ME-100, SOMASIF MAE, SOMASIF MTE, SOMASIF MEE, SOMASIF MPE (trade name, all manufactured by CO-OP CHEMICAL Co. Ltd.); S-BEN, S-BEN C, S-BEN E, S-BEN W, S-BEN P, S-BEN WX, S-BEN-400, S-BEN NX80, S-BEN NO12S, S-BEN NEZ, S-BEN NO12, S-BEN NE, S-BEN NZ70, ORGANAIT (trade names, all HOJUN Co., manufactured by Ltd.); KUNIPIA F, KUNIPIA G4 (trade name, manufactured by Kunimine Industries, co.ltd.); TIXOGEL VZ, CLAYTONE HT, CLAYTONE 40 (trade names, all manufactured by Rockwood Additives Limited).

The oxidized polyolefin may be prepared by itself, or a commercially available product may be used. Examples of the commercially available products include DISPARON 4200-20 (trade name, manufactured by NAKANGCHENJIU Co., Ltd.), FLOWNON SA300 (trade name, manufactured by Kyoho chemical Co., Ltd.), and the like.

The modified urea is a reactant of an isocyanate monomer or an adduct thereof and an organic amine. The modified urea may be prepared by itself or may be a commercially available product. Examples of the commercially available products include BYK410 (manufactured by BYK-Chemie Corporation).

The thixotropy-imparting agent may be used alone or in combination of two or more.

The proportion of the thixotropy-imparting agent in the antiglare layer (B) is preferably in the range of 0.2 to 5 parts by weight, more preferably in the range of 0.4 to 4 parts by weight, based on 100 parts by weight of the resin.

The maximum thickness (d') of the antiglare layer (B) is not particularly limited, and is preferably within a range of 3 to 12 μm. By setting the maximum thickness (d') of the antiglare layer (B) in the above range, for example, curling of the antiglare film can be prevented, and a problem of a decrease in productivity such as a conveyance failure can be avoided. When the thickness (D) is in the above range, the weight average particle diameter (D) of the fine particles is preferably in the range of 4 to 9 μm as described above. By setting the maximum thickness (D') of the antiglare layer (B) and the weight-average particle diameter (D) of the fine particles to the above combination, an antiglare film having excellent antiglare properties can be obtained. The maximum thickness (d') of the antiglare layer (B) is more preferably in the range of 4 to 8 μm.

The ratio D/D 'of the thickness (D') of the antiglare layer (B) to the weight-average particle diameter (D) of the fine particles may be, for example, 1 or less, less than 1, 0.98 or less, 0.96 or less, 0.93 or less, or 0.90 or less, and may be 0.5 or more, 0.6 or more, 0.7 or more, or 0.8 or more. By having such a relationship, an antiglare film having more excellent antiglare properties and capable of suppressing reflection glare can be obtained. For example, when D/D' is large, Ry and θ a tend to increase easily.

The antiglare film of the present invention may be, for example: the antiglare layer (B) has a collection portion in which a convex portion is formed on the surface of the antiglare layer (B) due to the collection of the filler, and the filler is present in a state where a plurality of fillers are collected in one direction of the surface of the antiglare layer (B) in the collection portion in which the convex portion is formed. This can prevent, for example, reflection glare of a fluorescent lamp. However, the antiglare film of the present invention is not limited thereto.

The surface shape of the antiglare layer (B) can be designed by adjusting, for example, the film thickness t obtained by subtracting the maximum height Ry 'of the irregularities of the antiglare layer (B) from the maximum thickness D' of the antiglare layer (B), and the weight-average particle diameter D of the fine particles. Specifically, for example, when the weight average particle diameter D of the fine particles is relatively large with respect to the film thickness t of the antiglare layer (B), Ry and θ a tend to increase. The film thickness t can be adjusted by, for example, the coating thickness of the resin. Further, the surface shape of the antiglare layer (B) can also be designed by adjusting the weight part of the fine particles relative to 100 parts by weight of the resin in the antiglare layer forming material. For example, when the weight fraction of the fine particles is relatively large relative to the resin, θ a tends to increase easily.

The antiglare film of the present invention may have, for example, an intermediate layer between the light-transmitting substrate (a) and the antiglare layer (B), the intermediate layer containing a resin derived from the light-transmitting substrate (a) and a resin derived from the antiglare layer (B). By controlling the thickness of the intermediate layer, the surface shape of the antiglare layer (B) can be controlled. For example, when the thickness of the intermediate layer is increased, Ry and θ a tend to be increased, and when the thickness of the intermediate layer is decreased, Ry and θ a tend to be decreased.

In the present invention, the mechanism of forming the intermediate layer (also referred to as a permeation layer or a compatibility layer) is not particularly limited, and is formed, for example, by the drying step in the method for producing an antiglare film of the present inventors. Specifically, for example, in the drying step, the coating liquid for forming the antiglare layer (B) penetrates into the light-transmitting substrate (a), and the intermediate layer including the resin derived from the light-transmitting substrate (a) and the resin derived from the antiglare layer (B) is formed. The resin contained in the intermediate layer is not particularly limited, and may be, for example, a resin obtained by simply mixing (compatibilizing) the resin contained in the light-transmitting substrate (a) and the resin contained in the antiglare layer (B). In addition, at least one of the resin contained in the intermediate layer, for example, the resin contained in the light-transmitting substrate (a) and the resin contained in the antiglare layer (B) may be chemically changed by heating, light irradiation, or the like.

The thickness ratio R of the intermediate layer defined by the following formula (5) is not particularly limited, and may be, for example, 0.10 to 0.80, for example, 0.15 or more, 0.20 or more, 0.25 or more, 0.30 or more, 0.40 or more, or 0.45 or more, and may be, for example, 0.75 or less, 0.70 or less, 0.65 or less, 0.60 or less, 0.50 or less, 0.40 or less, 0.45 or less, or 0.30 or less. The thickness ratio R of the intermediate layer may be, for example, 0.15 to 0.75, 0.20 to 0.70, 0.25 to 0.65, 0.30 to 0.60, 0.40 to 0.50, 0.45 to 0.50, 0.15 to 0.45, 0.15 to 0.40, 0.15 to 0.30, or 0.20 to 0.30. The intermediate layer can be confirmed by observing the cross section of the antiglare film with a Transmission Electron Microscope (TEM), for example, and the thickness can be measured.

R＝[D_C/(D_C+D_B)] (5)

In the above numerical formula (5), D_BThe thickness of the anti-glare layer (B) [ mu m ]]，D_CIs the thickness [ mu ] m of the intermediate layer]。

The surface shape of the antiglare layer (B) can also be designed by controlling the aggregation state of the filler contained in the antiglare layer-forming material. The aggregation state of the filler can be controlled by, for example, the material of the filler (for example, the chemical modification state of the surface of the fine particles, the affinity for a solvent and/or a resin, or the like), the type or combination of a resin (binder) and a solvent. In addition, the aggregation state of the fine particles can be precisely controlled by the thixotropy-imparting agent.

The antiglare film of the present invention may be a film in which the convex portion has a gentle shape and which can prevent the formation of a protrusion on the surface of the antiglare layer (B) which causes an appearance defect, but is not limited thereto. The antiglare film of the present invention may contain a plurality of the fine particles at a position directly or indirectly overlapping the antiglare layer (B) in the thickness direction thereof, for example.

The other layer is not particularly limited, and may be, for example, a low refractive index layer, an antireflection layer, a high refractive index layer, a hard coat layer, an adhesive layer, or the like as described above. The other layer may be one layer or a plurality of layers, and in the case of a plurality of layers, one or a plurality of layers may be provided. For example, the other layer may be an optical film whose thickness and refractive index are strictly controlled or a laminate of two or more layers of the optical film.

[2. method for producing antiglare film ]

The method for producing the antiglare film of the present invention is not particularly limited, and the antiglare film can be produced by any method, and is preferably produced by the method for producing the antiglare film of the present invention.

The method for producing the antiglare film can be performed, for example, as follows.

First, the antiglare layer (B) is formed on the light-transmitting substrate (a) so as to satisfy the above expressions (1) and (2) (antiglare layer (B) forming step). Thereby producing a laminate of the light-transmitting substrate (a) and the antiglare layer (B). The antiglare layer (B) forming step includes, as described above, a coating step of applying a coating liquid to the light-transmitting substrate (a) and a coating film forming step of drying the applied coating liquid to form a coating film. For example, the step of forming the antiglare layer (B) may further include a curing step of curing the coating film. The curing may be performed after the drying, for example, but is not limited thereto. The curing may be performed by, for example, heating, light irradiation, or the like. The light is not particularly limited, and may be, for example, ultraviolet light. The light source for the light irradiation is not particularly limited, and may be, for example, a high-pressure mercury lamp.

The coating liquid contains a resin and a solvent as described above. The coating liquid may be, for example, an antiglare layer forming material (coating liquid) containing the resin, the particles, the thixotropy imparting agent, and the solvent.

The coating liquid preferably exhibits thixotropy, and a Ti value defined by the following formula is preferably in the range of 1.3 to 3.5, more preferably in the range of 1.4 to 3.2, and still more preferably in the range of 1.5 to 3.

Ti value of beta 1/beta 2

In the above formula,. beta.1 is a viscosity measured at a shear rate of 20(1/s) using RHEOSTRES RS6000 manufactured by HAAKE, and. beta.2 is a viscosity measured at a shear rate of 200(1/s) using RHEOSTRES RS6000 manufactured by HAAKE.

When the Ti value is 1.3 or more, appearance defects are less likely to occur, and the characteristics of antiglare property and white bloom are less likely to be deteriorated. When the Ti value is 3.5 or less, the particles are less likely to be dispersed without aggregation.

The coating liquid may or may not contain a thixotropy-imparting agent, and is preferably one that easily exhibits thixotropy when it contains a thixotropy-imparting agent. In addition, as described above, by including the thixotropy-imparting agent in the coating liquid, an effect of preventing the particles from settling (thixotropy effect) can be obtained. Further, the surface shape of the antiglare film can be freely controlled in a wider range by shear aggregation of the thixotropy-imparting agent itself.

The solvent is not particularly limited, and various solvents can be used, and one solvent may be used alone, or two or more solvents may be used in combination. In order to obtain the antiglare film of the present invention, the most suitable type and ratio of the solvent may be appropriately selected depending on the composition of the resin, the types and contents of the particles and the thixotropy imparting agent. The solvent is not particularly limited, and examples thereof include: alcohols such as methanol, ethanol, Isopropanol (IPA), butanol, tert-butanol (TBA), and 2-methoxyethanol; ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone, and cyclopentanone; esters such as methyl acetate, ethyl acetate, and butyl acetate; ethers such as diisopropyl ether and propylene glycol monomethyl ether; glycols such as ethylene glycol and propylene glycol; cellosolves such as ethyl cellosolve and butyl cellosolve; aliphatic hydrocarbons such as hexane, heptane and octane; aromatic hydrocarbons such as benzene, toluene, and xylene. In addition, for example, the above solvent may include a hydrocarbon solvent and a ketone solvent. The hydrocarbon solvent may be, for example, an aromatic hydrocarbon. The aromatic hydrocarbon may be at least one selected from the group consisting of toluene, o-xylene, m-xylene, p-xylene, ethylbenzene, and benzene, for example. The ketone solvent may be, for example, at least one selected from the group consisting of cyclopentanone and acetone, methyl ethyl ketone, methyl isobutyl ketone, diethyl ketone, cyclohexanone, isophorone, and acetophenone. For example, in order to dissolve the thixotropy imparting agent (e.g., thickener), the above solvent preferably contains the above hydrocarbon solvent (e.g., toluene). The solvent may be, for example, a mixture of the hydrocarbon solvent and the ketone solvent in a ratio of 90: 10-10: 90 in a mass ratio of 90. The mass ratio of the hydrocarbon solvent to the ketone solvent may be, for example, 80: 20-20: 80. 70: 30-30: 70. or 40: 60-60: 40, etc. In this case, for example, the hydrocarbon solvent may be toluene, and the ketone solvent may be methyl ethyl ketone. In addition, the solvent may further include at least one selected from the group consisting of ethyl acetate, butyl acetate, IPA, methyl isobutyl ketone, methyl ethyl ketone, methanol, ethanol, and TBA, in addition to toluene, for example.

For example, when an acrylic film is used as the light-transmitting substrate (a) to form the intermediate layer (permeation layer), a good solvent for the acrylic film (acrylic resin) can be suitably used. As the solvent, for example, a solvent containing a hydrocarbon solvent and a ketone solvent may be mentioned as described above. The hydrocarbon solvent may be, for example, an aromatic hydrocarbon. The aromatic hydrocarbon may be at least one selected from the group consisting of toluene, o-xylene, m-xylene, p-xylene, ethylbenzene, and benzene, for example. The ketone solvent may be, for example, at least one selected from the group consisting of cyclopentanone, acetone, methyl ethyl ketone, methyl isobutyl ketone, diethyl ketone, cyclohexanone, isophorone, and acetophenone. The solvent may be, for example, a mixture of the hydrocarbon solvent and the ketone solvent in a ratio of 90: 10-10: 90 in a mass ratio of 90. The mass ratio of the hydrocarbon solvent to the ketone solvent may be, for example, 80: 20-20: 80. 70: 30-30: 70. or 40: 60-60: 40, etc. In this case, for example, the hydrocarbon solvent may be toluene, and the ketone solvent may be methyl ethyl ketone.

For example, when cellulose Triacetate (TAC) is used as the light-transmissive substrate (a) to form the intermediate layer (permeation layer), a good solvent for TAC can be suitably used. Examples of the solvent include ethyl acetate, methyl ethyl ketone, and cyclopentanone.

In addition, by appropriately selecting the solvent, the thixotropy of the antiglare layer forming material (coating liquid) can be favorably exhibited when the thixotropy imparting agent is contained. For example, when an organoclay is used, toluene and xylene may be suitably used alone or in combination, for example, when an oxidized polyolefin is used, methyl ethyl ketone, ethyl acetate, propylene glycol monomethyl ether may be suitably used alone or in combination, for example, when a modified urea is used, butyl acetate and methyl isobutyl ketone may be suitably used alone or in combination.

Various leveling agents may be added to the antiglare layer-forming material. As the leveling agent, for example, a fluorine-based or silicone-based leveling agent can be used for the purpose of preventing coating unevenness (uniformity of the coated surface). In the present invention, the leveling agent can be appropriately selected depending on the case where antifouling property is required for the surface of the antiglare layer (B), the case where an antireflection layer (low refractive index layer) or a layer containing an interlayer filler is formed on the antiglare layer (B) as described later, or the like. In the present invention, for example, by including the thixotropy imparting agent, the coating liquid can be made to exhibit thixotropy, and thus coating unevenness is less likely to occur. In this case, for example, there is an advantage that the alternatives of the leveling agent described above can be increased.

The amount of the leveling agent is, for example, 5 parts by weight or less, preferably 0.01 to 5 parts by weight, based on 100 parts by weight of the resin.

The antiglare layer forming material may contain, as necessary, a pigment, a filler, a dispersant, a plasticizer, an ultraviolet absorber, a surfactant, an antifouling agent, an antioxidant, and the like, as long as the performance is not impaired. These additives may be used alone or in combination of two or more.

For the antiglare layer forming material, a conventionally known photopolymerization initiator as described in, for example, japanese patent application laid-open No. 2008-88309 can be used.

As a method for forming a coating film by applying the coating liquid to the light-transmitting base material (a), for example, a coating method such as a jet coating method, a die coating method, a spin coating method, a spray coating method, a gravure coating method, a roll coating method, or a bar coating method can be used.

Next, the coating film is dried and cured as described above to form the antiglare layer (B). The drying may be, for example, natural drying, air drying, heat drying, or a combination thereof.

The drying temperature of the coating liquid for forming the antiglare layer (B) may be, for example, in the range of 30 to 200 ℃. The drying temperature may be, for example, 40 ℃ or higher, 50 ℃ or higher, 60 ℃ or higher, 70 ℃ or higher, 80 ℃ or higher, 90 ℃ or higher, or 100 ℃ or higher, and may be 190 ℃ or lower, 180 ℃ or lower, 170 ℃ or lower, 160 ℃ or lower, 150 ℃ or lower, 140 ℃ or lower, 135 ℃ or lower, 130 ℃ or lower, 120 ℃ or lower, or 110 ℃ or lower. The drying time is not particularly limited, and may be, for example, 30 seconds or more, 40 seconds or more, 50 seconds or more, or 60 seconds or more, or 150 seconds or less, 130 seconds or less, 110 seconds or less, or 90 seconds or less.

The curing means of the coating film is not particularly limited, but ultraviolet curing is preferred. The irradiation amount of the energy ray source is preferably 50 to 500mJ/cm in terms of the cumulative exposure amount at an ultraviolet wavelength of 365nm². The irradiation dose is 50mJ/cm²As described above, the curing easily proceeds sufficiently, and the hardness of the antiglare layer (B) to be formed easily increases. In addition, if it is 500mJ/cm²The formed antiglare layer (B) can be prevented from coloring as follows.

In this manner, a laminate of the light-transmitting substrate (a) and the antiglare layer (B) can be produced. The laminate may be used as it is as the antiglare film of the present invention, or the other layer may be formed on the antiglare layer (B) as the antiglare film of the present invention. The method for forming the other layer is not particularly limited, and for example, the formation may be carried out in the same manner as the conventional methods for forming a low refractive index layer, an antireflection layer, a high refractive index layer, a hard coat layer, an adhesive layer, and the like, or by methods based on these methods

[ 3] optical Member and image display device ]

The optical member of the present invention is not particularly limited, and may be, for example, a polarizing plate. The polarizing plate is not particularly limited, and may include, for example, the antiglare film of the present invention and a polarizer, and may further include other components. The components of the polarizing plate may be bonded to each other with an adhesive or a bonding agent, for example.

The image display device of the present invention is not particularly limited, and may be any image display device, and examples thereof include a liquid crystal display device and an organic EL display device.

The image display device of the present invention may be, for example, an image display device having the antiglare film of the present invention on a visual recognition side surface, and the image display device has a black matrix pattern.

The antiglare film of the present invention can be produced by, for example, bonding the light-transmitting substrate (a) side to an optical member for LCD with an adhesive or a bonding agent. In the case of this bonding, the surface of the light-transmitting substrate (a) may be subjected to various surface treatments as described above. As described above, according to the method for producing an antiglare film of the present invention, the surface shape of the antiglare film can be freely controlled in a wider range. Therefore, the optical properties obtained by laminating the antiglare film and another optical member using an adhesive, a pressure-sensitive adhesive, or the like can cover a wide range corresponding to the surface shape of the antiglare film.

Examples of the optical member include a polarizer and a polarizing plate. The polarizing plate is generally configured to have a transparent protective film on one side or both sides of a polarizer. When transparent protective films are provided on both surfaces of the polarizer, the transparent protective films on the front and back surfaces may be made of the same material or different materials. The polarizing plates are generally disposed on both sides of the liquid crystal cell. The polarizing plates were arranged so that the absorption axes of the 2 polarizing plates were substantially orthogonal to each other.

The configuration of the polarizing plate on which the antiglare film is laminated is not particularly limited, and for example, a configuration may be adopted in which a transparent protective film, the polarizer, and the transparent protective film are laminated in this order on the antiglare film, or a configuration may be adopted in which the polarizer and the transparent protective film are laminated in this order on the antiglare film.

The image display device of the present invention has the same configuration as the conventional image display device except that the antiglare film is disposed in a specific direction. For example, in the case of an LCD, it can be manufactured by appropriately assembling optical members such as a liquid crystal cell and a polarizing plate and components such as an illumination system (backlight and the like) used as needed, and incorporating a driver circuit and the like.

According to the antiglare film of the present invention, for example, strong external light can be scattered and reflection can be suppressed, and therefore reflection glare can be suppressed also outdoors. Therefore, the image display device of the present invention can be suitably used as, for example, a public information display for outdoor use, and the like. However, the image display device of the present invention is not limited to this application, and can be used for any other application. Examples of other applications include OA equipment such as a personal computer monitor, a notebook computer, and a copying machine, portable equipment such as a mobile phone, a clock, a digital camera, a Personal Digital Assistant (PDA), and a portable game machine, home electric equipment such as a video camera, a television, and a microwave oven, a rear view monitor, a monitor for a car navigation system, a vehicle-mounted equipment such as a car audio, a display equipment such as an information monitor for a commercial store, a police equipment such as a monitor, a nursing monitor, and a nursing and medical equipment such as a medical monitor.

Examples

Next, examples of the present invention will be described together with comparative examples. However, the present invention is not limited to the following examples and comparative examples.

In the following examples and comparative examples, the parts of the substances are parts by mass (parts by weight) unless otherwise specified.

Production example 1 production of base film A

First, an imidized polymethyl methacrylate resin was produced by the same method as in production example 1 of jp 2010-284840 a, using a tandem reaction extruder in which 2 extrusion reactors were arranged in series. As the tandem reaction extruder, a corotating twin-screw extruder was used, each of which had a diameter of 75mm in the 1 st extruder and the 2 nd extruder and a L/D (ratio of the length L to the diameter D of the extruder) of 74. A quantitative feeder (manufactured by KUBOTA Co., Ltd.) was used for supplying the raw material resin to the raw material supply port of the 1 st extruder. The degree of pressure reduction in each vent hole in the 1 st extruder and the 2 nd extruder was-0.095 MPa. A pipe having a diameter of 38mm and a length of 2m was used for connecting the 1 st extruder and the 2 nd extruder. As the in-member pressure control mechanism for connecting the resin discharge port of the 1 st extruder and the raw material supply port of the 2 nd extruder, a constant flow pressure valve was used. Further, resin pressure gauges were provided at the outlet of the 1 st extruder, the center of the connecting member between the 1 st extruder and the 2 nd extruder, and the outlet of the 2 nd extruder, respectively. The resin pressure gauge can be used for adjusting the pressure in a member connecting the resin discharge port of the 1 st extruder and the raw material supply port of the 2 nd extruder, or for checking extrusion fluctuation.

The imidized polymethyl methacrylate resin was produced as follows. First, a polymethyl methacrylate resin (Mw: 10.5 ten thousand) as a raw material resin and monomethylamine as an imidizing agent were fed into a 1 st extruder to produce an imide resin intermediate 1. At this time, the maximum temperature of the extruder was 280 ℃, the screw rotation speed was 55rpm, the raw material resin supply amount was 150 kg/hr, and the amount of added monomethylamine was 2.0 parts per 100 parts of the raw material resin. Further, the pressure in the monomethylamine push-in section of the 1 st extruder was adjusted to 8MPa by a constant flow pressure valve provided in front of the raw material supply port of the 2 nd extruder. Next, the imide resin intermediate 1 was transferred to the 2 nd extruder, and the residual imidization reagent and by-products were devolatilized through the back vent and the vacuum vent. Then, a mixed solution of dimethyl carbonate and triethylamine as an esterifying agent was added to produce an imide resin intermediate 2. In this case, the cylinder temperature of the 2 nd extruder was 260 ℃, the screw rotation speed was 55rpm, the amount of dimethyl carbonate added was 3.2 parts per 100 parts of the raw material resin, and the amount of triethylamine added was 0.8 parts per 100 parts of the raw material resin. Further, the esterification agent was removed through an exhaust hole, and then extruded from a strand die, cooled in a water tank, and pelletized by a pelletizer, thereby obtaining an objective imidized polymethyl methacrylate resin. The imidized polymethyl methacrylate resin had an imidization ratio of 3.7% and an acid value of 0.29 mmol/g.

Next, 100 parts by weight of the imidized polymethyl methacrylate resin and 0.62 part by weight of a triazine-based ultraviolet absorber (trade name: T-712, manufactured by ADEKA) were mixed together at 220 ℃ using a twin-screw kneader to prepare resin pellets. The resin pellets were dried at 100.5kPa and 100 ℃ for 12 hours, and extruded from a T die at a die temperature of 270 ℃ by a single-screw extruder to be molded into a film shape (160 μm in thickness). Further, the film was stretched in the direction of transport at 150 ℃ in an atmosphere to a thickness of 80 μm. Subsequently, the film was stretched in a direction perpendicular to the film conveyance direction at 150 ℃ in an atmosphere to obtain a base film A ((meth) acrylic resin film) having a thickness of 40 μm. The obtained base film A had a light transmittance of 8.5% at a wavelength of 380nm, an in-plane retardation Re of 0.4nm and a thickness direction retardation Rth of 0.78 nm. The obtained base film A had a moisture permeability of 61g/m²24 hr. The transmittance was measured in a wavelength range of 200nm to 800nm using a spectrophotometer (device name; U-4100) manufactured by HITACHI HIGH-TECH corporation, and the transmittance at a wavelength of 380nm was read. The phase difference was measured at a wavelength of 590nm and 23 ℃ using a product name "KOBRA 21-ADH" manufactured by WANGZI MEASURING APPARATUS. The moisture permeability is measured by a method based on JIS K0208 under the conditions of a temperature of 40 ℃ and a relative humidity of 92%.

[ coating solution 1]

60 parts of pentaerythritol triacrylate (PETA) (trade name: Viscoat #300, concentration 80% manufactured by Osaka organic chemical INDUSTRIES, Ltd.), 40 parts of 15-functional urethane acrylic oligomer (trade name: NK OLIGO UA-53H, weight average molecular weight: 2300, concentration 100%) 20 parts of 4-hydroxybutyl acrylate (trade name: 4-HBA, concentration 100% manufactured by Osaka organic chemical INDUSTRIES, Ltd.), 1 part of leveling agent (DIC, trade name: GRANDIC PC-4100), 5 parts of photopolymerization initiator (IRGACURE 907 manufactured by BASF Japan, 5 parts of fine particles of crosslinked acrylic-styrene copolymer resin (trade name: SSX1055QXE, weight average particle diameter: 5.5 μm), 8 parts of thickening agent (thixotropy imparting agent, KMIN UNISTRIES CO, trade name: MECTON SAN manufactured by LTD, concentration adjusted to 6% with toluene, were mixed together, in a solid content concentration of 40% and a total amount of toluene and methyl ethyl ketone of 7: 3 to prepare a coating liquid 1 (composition for forming an antiglare layer).

[ coating solution 2]

Coating liquid 2 (composition for forming an antiglare layer) was prepared in the same manner as in coating liquid 1 except that the fine particles of the crosslinked acrylic-styrene copolymer resin in coating liquid 1 were changed to 6 parts by weight of the fine particles of the crosslinked acrylic-styrene copolymer resin having a weight average particle diameter of 3.0 μm.

[ coating solution 3]

Coating liquid 3 (composition for forming an antiglare layer) was prepared in the same manner as in coating liquid 1 except that 20 parts of the fine particles of the crosslinked acrylic-styrene copolymer resin in coating liquid 1 were changed to 20 parts of the fine particles of the crosslinked acrylic-styrene copolymer resin having a weight average particle diameter of 8.0 μm.

< method of measurement >

[ surface shape measurement ]

A glass plate (thickness 1.3mm) manufactured by Songhua Nitri industries, Ltd was bonded to the surface of the antiglare film on which the antiglare layer was not formed with an adhesive, and the surface shape of the antiglare layer (B) was measured under a condition of a cutoff value of 0.8mm using a high-precision fine shape measuring instrument (trade name; SURFCORDER ET4000, manufactured by Satsuka research Co., Ltd.), and the maximum height and the average inclination angle were calculated. Further, the average values obtained by measuring the maximum height and the average inclination angle at arbitrary 10 points are defined as the maximum height Ry and the average inclination angle θ a, respectively. The high-precision fine shape measuring device may automatically calculate the maximum height Ry and the average inclination angle θ a. The method of measuring and calculating the maximum height Ry and the average inclination angle θ a are based on JIS B0601 (1994 version).

[ reflection glare ]

(1) A black acrylic plate (made by Mitsubishi Yang, Ltd., thickness: 2.0mm) was bonded to the surface of the antiglare film on which the antiglare layer was not formed with an adhesive, and a sample having no back reflection was prepared.

(2) In an office environment (about 1000Lx) where a display is generally used, the sample is irradiated with a fluorescent lamp (three-wavelength light source) from a position 50cm away from the front direction, and the antiglare property of the sample is determined by visual observation from the position 50cm away from the front direction based on the following criteria.

Criterion for determination

_◎: has excellent antiglare properties and does not leave any reflection glare of a fluorescent lamp pinnate image.

_〇: and_◎the glare-proof property is inferior to the glare-proof property, but the reflection glare can be prevented without any problem.

_△: and_〇it is inferior to the antiglare property, but the contour of the fluorescent lamp is slightly blurred.

X: the fluorescent lamp's contour is not blurred and clearly reflected.

[ oblique reflection flare ]

The oblique reflection glare test was performed in the same manner as the reflection glare test except that the fluorescent lamp was irradiated from a position which was inclined at 30 ° to the front surface of the sample and was separated by 50cm, and the position which was inclined at 30 ° to the front surface of the sample and was separated by 50cm was visually determined based on the following criteria.

Criterion for determination

X: the fluorescent lamp's contour is not blurred and clearly reflected.

[ film thickness t ]

The maximum thickness of the antiglare layer (B) was measured at the same point as the measurement point of the maximum height Ry by the high-precision fine shape measuring instrument (trade name; SURFCORDER ET4000, produced by Okawa Katsuka research Co., Ltd.). The average of the measured values of the maximum thickness at the 10 points is defined as the maximum thickness d of the antiglare layer (B). The value obtained by subtracting the maximum height Ry from the maximum thickness d is defined as the film thickness t of the antiglare layer (B). The high-precision fine shape measuring device may automatically calculate the maximum thickness d and the film thickness t. In the present example and the comparative example, since the maximum thickness d is almost equal to the weight average particle diameter of the fine particles, the film thickness t can be approximated by a value obtained by subtracting the maximum height Ry from the weight average particle diameter.

[ haze value ]

In the method for measuring the haze value, the haze (opacity) based on JIS K7136 (2000 edition) was measured by separately providing an antiglare film using a haze meter (product name "HM-150" by the color technology research on village, ltd.).

[ example 1]

The coating liquid 1 was applied (coated) on one surface of the base material (light-transmitting base material (a)) of production example 1 to form a coating layer (coating layer). Then, the coating layer was dried by heating at 90 ℃ for 1 minute to form a coating film. Then, the coating film was irradiated with a cumulative light amount of 300mJ/cm by a high-pressure mercury lamp²The ultraviolet ray (c) is cured to form the antiglare layer (B), thereby obtaining the intended antiglare film. The maximum height Ry of the antiglare layer (B) was 4.6 μm. In the present embodiment, the antiglare layer (B) is an antiglare hard coat layer. The same applies to the following examples and comparative examples.

[ example 2]

An antiglare film was obtained in the same manner as in example 1, except that the thickness of the coating film was changed to set the maximum height Ry of the antiglare layer (B) to 2.6 μm.

[ example 3]

An antiglare film was obtained in the same manner as in example 1, except that the thickness of the coating film was changed to set the maximum height Ry of the antiglare layer (B) to 1.8 μm.

Comparative example 1

An antiglare film was obtained in the same manner as in example 1, except that the thickness of the coating film was changed to set the maximum height Ry of the antiglare layer (B) to 1.1 μm.

Comparative example 2

The coating liquid obtained by removing 8 parts of fine particles of the crosslinked acrylic-styrene copolymer resin (product name: SSX1055QXE, average particle diameter: 5.5 μm, manufactured by waterlogging chemical Co., Ltd.) from the coating liquid 1 was applied again to the antiglare layer (A) in the antiglare film of example 2. Then, the layer obtained by the above coating was dried and cured by the same method as in example 1 to form an antiglare layer. The maximum height Ry of the antiglare layer was 0.64 μm.

Comparative example 3

An antiglare film was obtained in the same manner as in example 1, except that the coating liquid 1 was changed to the coating liquid 2 and the maximum height Ry of the antiglare layer (B) was changed to 1.5 μm.

Comparative example 4

An antiglare film was obtained in the same manner as in comparative example 3, except that the thickness of the coating film was changed to set the maximum height Ry of the antiglare layer (B) to 1.1 μm.

Comparative example 5

An antiglare film was obtained in the same manner as in comparative example 3, except that the thickness of the coating film was changed to set the maximum height Ry of the antiglare layer (B) to 2.4 μm. Then, 8 parts of a coating liquid obtained by removing fine particles of a crosslinked acrylic-styrene copolymer resin (product name: SSX1055QXE, manufactured by waterlogging chemical Co., Ltd., average particle diameter: 5.5 μm) from the coating liquid 1 was applied again to the antiglare layer (A) in the antiglare film. Then, the layer obtained by the above coating was dried and cured by the same method as in example 1 to form an antiglare layer. The maximum height Ry of the antiglare layer was 0.55 μm.

[ example 4]

An antiglare film was obtained in the same manner as in example 1, except that the coating liquid 1 was changed to the coating liquid 3, and the maximum height Ry of the antiglare layer (B) was changed to 6.9 μm.

[ example 5]

An antiglare film was obtained in the same manner as in example 1, except that the coating liquid 1 was changed to the coating liquid 3 and the maximum height Ry of the antiglare layer (B) was changed to 4.5 μm.

[ example 6]

An antiglare film was obtained in the same manner as in example 1, except that the coating liquid 1 was changed to the coating liquid 3 and the maximum height Ry of the antiglare layer (B) was changed to 2.6 μm.

[ example 7]

An antiglare film was obtained in the same manner as in example 4, except that the thickness of the coating film was changed to set the maximum height Ry of the antiglare layer (B) to 1.8 μm.

Comparative example 6

An antiglare film was obtained in the same manner as in example 4, except that the thickness of the coating film was changed to set the maximum height Ry of the antiglare layer (B) to 1.2 μm.

Comparative example 7

The coating liquid obtained by removing 8 parts of fine particles of the crosslinked acrylic-styrene copolymer resin (product name: SSX1055QXE, manufactured by waterlogging chemical Co., Ltd., average particle diameter: 5.5 μm) from the coating liquid 1 was applied again to the antiglare layer (A) in the antiglare film of example 6. Then, the layer obtained by the above coating was dried and cured by the same method as in example 1 to form an antiglare layer. The maximum height Ry of the antiglare layer was 0.77 μm.

The film thickness t (the thickness obtained by subtracting the maximum height of the convexities and concavities from the maximum thickness of the antiglare layer (B)), the maximum height Ry of the convexities and concavities on the outermost surface, the average inclination angle θ a of the convexities and concavities on the outermost surface, the haze value, the reflection glare test results, and the oblique reflection glare test results of examples 1 to 7 and comparative examples 1 to 7 are summarized in table 1 below.

[ Table 1]

As shown in Table 1, examples 1 to 7 in which Ry and θ a satisfy the conditions of the present invention suppressed reflection glare. In contrast, the reflection glare in the front direction and the oblique direction is significant in comparative examples 2, 5, and 7 in which Ry and θ a are outside the scope of the present invention. In addition, comparative examples 1, 3, 4, and 6 in which θ a satisfies the conditions of the present invention but Ry is outside the range of the present invention have significant reflection glare in the oblique direction.

Industrial applicability

As described above, according to the present invention, an antiglare film, an optical member, and an image display device in which reflection glare is suppressed can be provided. According to the antiglare film of the present invention, for example, strong external light can be scattered and reflection can be suppressed, and therefore reflection glare can be suppressed even outdoors. Therefore, the present invention can be suitably used for an image display device such as an outdoor public information display. However, the present invention is not limited to this application, and can be used in a wide range of applications.

This application claims priority based on Japanese application laid-open at 2019, 4/10, and the entire disclosure of which is incorporated herein by reference.

Description of the reference numerals

10 antiglare film

11 light-transmitting substrate (A)

12 anti-dazzle layer (B)

12a resin layer

12b particles

12c thixotropy imparting agent

13 other layers

Maximum height of convex portion of the maximum surface of Ry

d maximum thickness of the translucent base material (A)

Particle size of D Fine particles

Maximum height of convex part of the unevenness of Ry' antiglare layer (B)

Maximum thickness of the d' antiglare layer (B)

Film thickness (d '-Ry') of t antiglare layer (B)

Claims

1. An antiglare film characterized in that an antiglare layer (B) is laminated on a light-transmitting substrate (A),

wherein unevenness is formed on the outermost surface of the antiglare film on the antiglare layer (B) side,

the unevenness satisfies the following numerical expressions (1) and (2),

Ry≥1.7 (1)

θa≥0.7 (2)

in the above formula (1), Ry is the maximum height [ μm ] of the convex portion of the concavity and convexity,

2. The antiglare film according to claim 1, wherein the antiglare layer (B) comprises fine particles.

3. The antiglare film according to claim 2, wherein an unevenness is formed on a surface of the antiglare layer (B) opposite to the light-transmitting substrate (A),

the weight-average particle diameter of the fine particles is larger than the thickness obtained by subtracting the maximum height of the convex portions of the unevenness from the maximum thickness of the antiglare layer (B).

4. The antiglare film according to claim 2 or 3, wherein the fine particles have a weight average particle diameter in the range of 4 to 9 μm.

5. The antiglare film according to any one of claims 1 to 4, wherein another layer is further laminated on a surface of the antiglare layer (B) opposite to the light-transmitting substrate (A).

6. An antiglare film characterized in that an antiglare layer (B) and another layer are laminated in this order on a light-transmitting substrate (A),

the other layer has a concave-convex formed on the outermost surface thereof,

the unevenness satisfies the following numerical expressions (1) and (2),

Ry≥1.7 (1)

θa≥0.7 (2)

7. A method for producing an antiglare film according to any one of claims 1 to 6, comprising an antiglare layer (B) formation step of forming the antiglare layer (B) on the light-transmitting substrate (A) so as to satisfy the formulae (1) and (2),

the step of forming the antiglare layer (B) comprises: a coating step of coating the light-transmitting substrate (a) with a coating liquid; and a coating film forming step of forming a coating film by drying the coating liquid applied,

the coating liquid contains a resin and a solvent.

8. The production method according to claim 7, wherein the antiglare layer (B) forming step further comprises a curing step of curing the coating film.

9. The manufacturing method according to claim 7 or 8, wherein the coating liquid contains fine particles.

10. An optical member comprising the antiglare film of any one of claims 1 to 6.

11. The optical member according to claim 10, which is a polarizing plate.

12. An image display device comprising the antiglare film of any one of claims 1 to 6 or the optical member of claim 10 or 11.

13. The image display device according to claim 12, which is a public information display.