Anti-reflection film and method for manufacturing the same

Abstract

To provide an anti-reflection film that is excellent in anti-fouling properties and high-temperature durability while preventing reflection of external light, and can reduce an environmental load, and a method for manufacturing the same.SOLUTION: An anti-reflection film 10 has, in this order, a transparent film base material 11, a hard coat layer 12, an anti-reflection layer 13, and an anti-fouling layer 14 including a fluorine-containing compound. The anti-reflection layer 13 and the anti-fouling layer 14 are in contact with each other. A principal surface 14a of the anti-fouling layer 14, which is on the opposite side of a surface facing the anti-reflection layer 13, has a maximum height Rz of 0.40 μm or more.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to an anti-reflection film and a method for producing the same. [Background technology]

[0002] An anti-reflection film is disposed on the viewing side of image display devices such as liquid crystal displays and organic EL displays for the purposes of preventing degradation of image quality due to reflection of external light, improving contrast, etc. The anti-reflection film comprises an anti-reflection layer made of a laminate of multiple thin films with different refractive indices on a transparent film substrate.

[0003] For example, Patent Document 1 discloses an antireflection film that includes a SiO primer layer on a hard coat film, and an antireflection layer thereon consisting of an alternating laminate of a niobium oxide (Nb2O5) layer as a high refractive index layer and a silicon oxide (SiO2) layer as a low refractive index layer. Patent Document 1 also describes that an antifouling layer obtained from a fluorine-containing compound may be provided as the outermost layer of the antireflection film. By providing the antifouling layer, the surface of the antireflection film becomes less susceptible to dirt, and even if dirt does become attached, wiping performance can be improved.

[0004] Furthermore, Patent Document 1 describes a method for producing a laminate having an antireflection layer made of the above-mentioned alternating laminate and a polarizer. Specifically, Patent Document 1 describes a method for producing an antireflection film by forming an SiO primer layer and an antireflection layer on a glow plasma-treated film substrate, and then laminating this antireflection film with a polarizer or the like to obtain the laminate. Hereinafter, a laminate having at least an antireflection layer and a polarizer may be referred to as a "polarizer-attached antireflection film." An antireflection film with a polarizer can be used as a polarizing plate with antireflection properties. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2009-47876 Summary of the Invention [Problem to be solved by the invention]

[0006] In general, polarizer-equipped antireflection films used in in-vehicle image display devices are required to undergo less change (particularly, less appearance change such as the occurrence of color unevenness) at higher temperatures (e.g., 90°C or higher) than polarizer-equipped antireflection films used in mobile devices intended for outdoor use. In other words, antireflection films used in in-vehicle image display devices are required to be able to suppress changes in the film at high temperatures (e.g., the occurrence of color unevenness) when attached to a polarizer. Hereinafter, the ability to suppress changes in the film at high temperatures when attached to a polarizer may be referred to as "high-temperature durability."

[0007] Using only the technology described in Patent Document 1, it is difficult to obtain an anti-reflection film that suppresses reflection of external light, has excellent antifouling properties and high-temperature durability, and can reduce environmental impact.

[0008] In view of the above, an object of the present invention is to provide an anti-reflection film that suppresses reflection of external light, has excellent antifouling properties and high-temperature durability, and can reduce environmental impact, and a method for producing the same. [Means for solving the problem]

[0009] <Aspects of the present invention> The present invention includes the following aspects.

[0010] [1] An antireflection film having a transparent film substrate, a hard coat layer, an antireflection layer, and an antifouling layer containing a fluorine-containing compound in this order, the antireflection layer and the antifouling layer are in contact with each other, a surface layer of the antireflection layer on the side of the antifouling layer is a thin film containing silicon oxide as a main component and having a thickness of 10 nm or more; a maximum height Rz of the main surface of the antifouling layer opposite to the antireflection layer side is 0.40 μm or more; a composition ratio of fluorine to silicon, F / Si, on the main surface of the antifouling layer is 3.00 or more; when the composition ratio F / Si in the thickness direction of the antifouling layer and the antireflection layer is measured by X-ray photoelectron spectroscopy while etching the antifouling layer and the antireflection layer, the composition ratio F / Si at a location at a depth of 10 nm from the main surface of the antifouling layer side of the antireflection layer is 0.02 or less, The moisture permeability of the antireflection layer is 20 g / m 2 Anti-reflective film for 24 hours or more.

[0011] [2] The moisture permeability of the antireflection layer is 1000 g / m 2 The anti-reflection film according to [1] above, wherein the anti-reflection film has a life span of 24 hours or less.

[0012] [3] The antireflection film according to [1] or [2], wherein the antireflection layer further comprises a high refractive index layer having a refractive index higher than that of the thin film containing silicon oxide as a main component.

[0013] [4] The antireflection film according to any one of [1] to [3] above, wherein the hard coat layer contains particles with a number average primary particle diameter of 0.5 μm or more.

[0014] [5] The antireflection film according to any one of [1] to [4] above, further comprising a primer layer disposed between the hard coat layer and the antireflection layer.

[0015] [6] The anti-reflection film according to any one of [1] to [5] above, further comprising a pressure-sensitive adhesive layer disposed on the transparent film substrate on the side opposite to the hard coat layer side.

[0016] [7] A method for producing an antireflection film according to any one of [1] to [6] above, A step Sa of preparing a transparent film substrate having a hard coat layer; a step Sb of subjecting a main surface of the hard coat layer opposite to the transparent film substrate side to a plasma treatment in the presence of oxygen gas; a step Sc of forming an anti-reflection layer on the plasma-treated main surface side; and forming an antifouling layer on the main surface of the antireflection layer opposite to the hard coat layer side. [Effects of the Invention]

[0017] According to the present invention, it is possible to provide an antireflection film that suppresses reflection of external light, has excellent antifouling properties and high-temperature durability, and can reduce environmental impact, and a method for producing the same. [Brief explanation of the drawings]

[0018] [Figure 1] 1 is a cross-sectional view showing an example of an anti-reflection film according to the present invention. [Figure 2] FIG. 2 is a cross-sectional view showing another example of the anti-reflection film according to the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0019] Preferred embodiments of the present invention will be described below. First, the terms used in this specification will be explained. "Refractive index" refers to the refractive index for light with a wavelength of 550 nm in an atmosphere at a temperature of 23°C. The "main surface" of a layered material (more specifically, a transparent film substrate, a hard coat layer, an anti-reflection layer, an anti-fouling layer, a pressure-sensitive adhesive layer, etc.) refers to a surface perpendicular to the thickness direction of the layered material. Unless otherwise specified, the numerical value of the "thickness (film thickness)" of each layer constituting the anti-reflection film is the arithmetic average of 10 measurement values ​​obtained by randomly selecting 10 measurement points from an image of a cross section cut in the thickness direction of the layer and measuring the thickness of the selected 10 measurement points.

[0020] Unless otherwise specified, the "major component" of a thin film (layer) means the component that is contained in the thin film in the largest amount by weight. The "solid content" refers to non-volatile components in the composition, such as components other than the solvent.

[0021] Unless otherwise specified, the number average primary particle diameter of particles is the number average value of the equivalent circle diameters (Heywood diameter: diameter of a circle having the same area as the projected area of ​​a primary particle) of 100 primary particles measured using a scanning electron microscope and image processing software (for example, "ImageJ" manufactured by the National Institutes of Health, USA).

[0022] Hereinafter, the compound and its derivatives may be collectively referred to by adding "based" after the compound name. Furthermore, when the compound name is followed by "based" to represent the name of a polymer, unless otherwise specified, it means that the repeating unit of the polymer is derived from the compound or its derivative. Furthermore, acrylates and methacrylates may be collectively referred to as "(meth)acrylates."

[0023] Unless otherwise specified, the components, functional groups, etc. exemplified in this specification may be used alone or in combination of two or more kinds.

[0024] The drawings referred to in the following description mainly show each component in a schematic manner for ease of understanding, and the size, number, shape, etc. of each component shown may differ from the actual size, number, shape, etc. of each component due to the convenience of creating the drawings. Furthermore, for convenience of explanation, in drawings described later, the same components as those in previously described drawings may be assigned the same reference numerals, and their explanation may be omitted.

[0025] <First embodiment: anti-reflection film> The antireflection film according to the first embodiment of the present invention is a laminate having, in this order, a transparent film substrate, a hard coat layer, an antireflection layer, and an antifouling layer containing a fluorine-containing compound. The antireflection layer and the antifouling layer are in contact with each other. The surface layer of the antifouling layer on the antifouling layer side is a thin film containing silicon oxide as a main component and having a thickness of 10 nm or more. The maximum height Rz of the main surface of the antifouling layer opposite the antireflection layer side is 0.40 μm or more. The composition ratio F / Si of fluorine to silicon on the main surface of the antifouling layer opposite the antireflection layer side is 3.00 or more. When the composition ratio F / Si in the thickness direction of the antifouling layer and the antireflection layer is measured using X-ray photoelectron spectroscopy while etching the antifouling layer and the antireflection layer, the composition ratio F / Si at a depth of 10 nm from the main surface of the antifouling layer side of the antireflection layer is 0.02 or less. Furthermore, in the antireflection film according to the first embodiment, the moisture permeability of the antireflection layer is 20 g / m 2 - 24 hours or more.

[0026] The "composition ratio F / Si" means the value obtained by dividing the number of fluorine atoms by the number of silicon atoms (number of fluorine atoms / number of silicon atoms). The composition ratio F / Si is an index of the abundance ratio of fluorine-containing compounds. In other words, the larger the composition ratio F / Si, the more fluorine-containing compounds tend to be present.

[0027] Hereinafter, measuring the composition ratio F / Si in the thickness direction of the antifouling layer and the antireflection layer while etching the antifouling layer and the antireflection layer using X-ray photoelectron spectroscopy may be simply referred to as "measuring the composition ratio F / Si in the thickness direction." The method for measuring the composition ratio F / Si in the thickness direction is the same as or a similar method to that described in the Examples below. X-ray photoelectron spectroscopy may also be referred to as "XPS." The composition ratio F / Si of fluorine to silicon on the main surface of the antifouling layer opposite the antireflection layer side may also be referred to as the "surface composition ratio F / Si." The composition ratio F / Si at a depth of 10 nm from the main surface of the antifouling layer side of the antireflection layer obtained when measuring the composition ratio F / Si in the thickness direction may also be referred to as the "composition ratio F / Si at a depth of 10 nm."

[0028] The surface composition ratio F / Si is the composition ratio F / Si at the start of etching (etching time: 0 seconds) when the composition ratio F / Si in the thickness direction is measured. The "location 10 nm deep from the antifouling layer-side principal surface of the antireflection layer" refers to the location where the depth obtained by converting the etching time of the antireflection layer using the sputtering rate relative to SiO2 is 10 nm. Because the antifouling layer is instantly removed immediately after the start of etching, the etching time for etching the antifouling layer and the antireflection layer is essentially equal to the etching time for the antireflection layer. Therefore, the "location 10 nm deep from the antifouling layer-side principal surface of the antireflection layer" refers to the location where the depth obtained by converting the etching time when the composition ratio F / Si in the thickness direction of the antifouling layer and the antireflection layer is measured using the sputtering rate relative to SiO2 is 10 nm.

[0029] The anti-reflection film according to the first embodiment, having the above-mentioned configuration, can suppress reflection of external light, has excellent antifouling properties and high-temperature durability, and also reduces the environmental impact. The reasons for this are presumed to be as follows.

[0030] In the antireflection film according to the first embodiment, the maximum height Rz of the main surface of the antifouling layer (specifically, the main surface of the antifouling layer opposite the antireflection layer side) is 0.40 μm or more. Therefore, the antireflection film according to the first embodiment tends to have high antiglare properties. Therefore, the antireflection film according to the first embodiment can suppress the reflection of external light.

[0031] Furthermore, in the antireflection film according to the first embodiment, the surface composition ratio F / Si is 3.00 or more, and therefore the antireflection film according to the first embodiment has excellent antifouling properties due to the presence of a relatively large amount of fluorine-containing compounds on the surface of the antifouling layer.

[0032] Furthermore, in the antireflection film according to the first embodiment, the composition ratio F / Si at a depth of 10 nm is 0.02 or less. Therefore, the antireflection film according to the first embodiment has a relatively small amount of fluorine-containing compounds in areas other than the surface of the antifouling layer. Therefore, the antireflection film according to the first embodiment can reduce the content of, for example, organic fluorine compounds (PFAS), thereby reducing the environmental impact. Furthermore, in the antireflection film according to the first embodiment, the surface composition ratio F / Si is 3.00 or more, and the composition ratio F / Si at a depth of 10 nm is 0.02 or less, so that fluorine-containing compounds are present only near the surface of the antifouling layer. Antireflection films in which fluorine-containing compounds are present only near the surface of the antifouling layer tend to have excellent antifouling properties, such as fingerprint wiping properties.

[0033] In addition, in the antireflection film according to the first embodiment, the moisture permeability of the antireflection layer is 20 g / m 2 24 hours or more. Therefore, even if a polarizer-attached antireflection film including the antireflection film according to the first embodiment is placed in a heated environment, moisture in the polarizer is easily released to the outside through the antireflection layer. Therefore, the antireflection film according to the first embodiment can suppress deterioration of the polarizer due to moisture (for example, the occurrence of color unevenness), and therefore has excellent high-temperature durability.

[0034] Generally, when a polarizer-equipped antireflection film is exposed to a heated environment, moisture in the transparent film substrate or the polarizer evaporates outside the film. If the moisture permeability of the antireflection layer is low, moisture is less likely to diffuse outside the system. If moisture remains inside the film, triacetyl cellulose, for example, which constitutes the transparent film substrate, is more likely to be hydrolyzed, which tends to reduce the protective performance of the polarizer. Furthermore, hydrolysis of triacetyl cellulose generates free acid. In the presence of acid, polyvinyl alcohol, which constitutes the polarizer, is more likely to undergo polyenization, which causes deterioration of the polarizer. In contrast, if the moisture permeability of the antireflection layer is high, moisture evaporated from the polarizer or the transparent film substrate is more likely to diffuse outside the system from the surface of the antireflection layer, thereby suppressing moisture retention and thus suppressing deterioration of the polarizer-equipped antireflection film at high temperatures.

[0035] In the first embodiment, to obtain an antireflection film with superior antifouling properties, the surface composition ratio F / Si is preferably 3.50 or more, more preferably 4.00 or more, even more preferably 4.50 or more, and even more preferably 5.00 or more. In addition, in the first embodiment, to obtain an antireflection film that can further reduce the environmental load, the surface composition ratio F / Si is preferably 7.00 or less, more preferably 6.50 or less, and even more preferably 6.00 or less.

[0036] In the first embodiment, in order to obtain an antireflection film that can further reduce the environmental impact, the composition ratio F / Si at a depth of 10 nm is preferably 0.01 or less. The lower limit of the composition ratio F / Si at a depth of 10 nm is not particularly limited and may be 0.00.

[0037] In the first embodiment, in order to obtain an antireflection film having excellent high-temperature durability, the moisture permeability of the antireflection layer is set to 30 g / m 2 24 hours or more is preferable, 40 g / m 2 24 hours or more is preferable, and 50 g / m 2 Further, if the moisture permeability of the antireflection layer is excessively high, the durability under high humidity conditions tends to decrease. Therefore, the moisture permeability of the antireflection layer is preferably 1000 g / m 2 24 hours or less is preferable, and 800 g / m 2 It is more preferable that the moisture permeability is 24 hours or less. The moisture permeability is measured by the same method as in the examples described below or a method equivalent thereto. Note that the anti-reflection layer is a thin film, and it is difficult to determine the moisture permeability of the anti-reflection layer alone. However, since the moisture permeability of many resin films is significantly greater than that of inorganic oxide films, the moisture permeability of an anti-reflection film provided with an anti-reflection layer can be considered to be equal to the moisture permeability of the anti-reflection layer.

[0038] The configuration of the antireflection film according to the first embodiment will be described below with reference to the drawings. FIG. 1 is a cross-sectional view showing an example of the antireflection film according to the first embodiment. The antireflection film 10 shown in FIG. 1 has a transparent film substrate 11, a hard coat layer 12, an antireflection layer 13, and an antifouling layer 14, in this order. The antifouling layer 14 contains a fluorine-containing compound. In the antireflection film 10 shown in FIG. 1, the antifouling layer 14 is the outermost layer of the antireflection film 10. The antireflection layer 13 and the antifouling layer 14 are in contact with each other.

[0039] The antireflection layer 13 has four layers, in this order from the hard coat layer 12 side: a high refractive index layer 15, a low refractive index layer 16, a high refractive index layer 17, and a low refractive index layer 18. The low refractive index layer 18, which is the surface layer of the antireflection layer 13 on the antifouling layer 14 side, is a thin film containing silicon oxide as a main component and having a thickness of 10 nm or more. The low refractive index layer 18 may contain oxides other than silicon oxide. However, to more efficiently reduce reflected light, the content of silicon oxide in the low refractive index layer 18 is preferably 90 wt% or more, and more preferably 99 wt% or more, based on the total amount of the low refractive index layer 18. Hereinafter, a thin film containing silicon oxide as a main component may be referred to as a "silicon oxide layer." The high refractive index layer is a layer with a higher refractive index than the low refractive index layer. Details of the high refractive index layer and the low refractive index layer will be described later. The antireflection layer of the antireflection film is not limited to a four-layer structure like the antireflection layer 13, but may be a two-layer structure, a three-layer structure, a five-layer structure, or a stacked structure of six or more layers. The antireflection layer of the antireflection film may have a single layer structure consisting of only a silicon oxide layer. The antireflection layer of the antireflection film is preferably an alternate laminate of two or more high refractive index layers and two or more low refractive index layers.

[0040] The maximum height Rz of the principal surface 14a of the antifouling layer 14 opposite to the antireflection layer 13 side is 0.40 μm or more. The principal surface 14a of the antifouling layer 14 opposite to the antireflection layer 13 side has a composition ratio F / Si of fluorine to silicon (surface composition ratio F / Si) of 3.00 or more. When the composition ratio F / Si in the thickness direction is measured, the composition ratio F / Si at a depth of 10 nm from the principal surface 13a on the antifouling layer 14 side of the antireflection layer 13 (composition ratio F / Si at a depth of 10 nm) is 0.02 or less. The moisture permeability of the antireflection layer 13 is 20 g / m 2 - 24 hours or more.

[0041] The antireflection film 10 further includes a primer layer 19 disposed between the hard coat layer 12 and the antireflection layer 13. That is, the antireflection film 10 includes a transparent film substrate 11, a hard coat layer 12, a primer layer 19, an antireflection layer 13, and an antifouling layer 14, in this order.

[0042] The antireflection film may have a layer structure different from that of the antireflection film 10 shown in Fig. 1. For example, the antireflection film may be an antireflection film 20, as shown in Fig. 2, which further includes a pressure-sensitive adhesive layer 21 arranged on the side of the transparent film substrate 11 opposite to the hard coat layer 12 side.

[0043] The adhesive constituting adhesive layer 21 is not particularly limited, and can be appropriately selected and used from transparent adhesives whose base polymer is, for example, an acrylic polymer, a silicone polymer, polyester, polyurethane, polyamide, polyvinyl ether, a vinyl acetate-vinyl chloride copolymer, a modified polyolefin, an epoxy resin, a fluorine-based resin, natural rubber, synthetic rubber, etc. The thickness of adhesive layer 21 is not particularly limited, but is preferably 5 μm or more and 100 μm or less from the viewpoint of achieving both a thin layer and adhesiveness.

[0044] A release liner (not shown) may be temporarily attached to the main surface of the pressure-sensitive adhesive layer 21 opposite to the transparent film substrate 11 side. The release liner protects the surface of the pressure-sensitive adhesive layer 21, for example, until the anti-reflection film 20 is bonded to an image display panel (not shown). The release liner is preferably made of a plastic film formed from acrylic, polyolefin, cyclic polyolefin, polyester, or the like. The release liner has a thickness of, for example, 5 μm or more and 200 μm or less. The surface of the release liner is preferably subjected to a release treatment. Examples of materials for the release agent used in the release treatment include silicone-based materials, fluorine-based materials, long-chain alkyl-based materials, and fatty acid amide-based materials.

[0045] The configuration of the antireflection film according to the first embodiment has been described above with reference to the drawings, but the antireflection film according to the present invention is not limited to the above-mentioned configuration.

[0046] For example, the antireflection film according to the present invention may be an antireflection film that does not include a primer layer, or may include an optically functional layer different from the layers included in the above-described configuration (transparent film substrate, hard coat layer, primer layer, antireflection layer, and antifouling layer).

[0047] Next, the elements of the anti-reflection film according to the first embodiment will be described.

[0048] [Transparent film substrate] The transparent film substrate is, for example, a flexible, transparent resin film. Examples of materials constituting the transparent film substrate include polyester resins, polyolefin resins, polystyrene resins, acrylic resins, polycarbonate resins, polyethersulfone resins, polysulfone resins, polyamide resins, polyimide resins, cellulose resins, norbornene resins, polyarylate resins, and polyvinyl alcohol resins. Examples of polyester resins include polyethylene terephthalate (PET), polybutylene terephthalate, and polyethylene naphthalate. Examples of polyolefin resins include polyethylene, polypropylene, and cycloolefin polymer (COP). Examples of cellulose resins include triacetyl cellulose (TAC). These materials may be used alone or in combination. From the viewpoints of transparency and strength, the material for the transparent film substrate is preferably one selected from the group consisting of polyester resins, polyolefin resins, and cellulose resins, more preferably one selected from the group consisting of PET, COP, and TAC, and even more preferably TAC. In other words, as the transparent film substrate, a type of film selected from the group consisting of polyester resin film, polyolefin resin film, and cellulose resin film is preferred, a type of film selected from the group consisting of PET film, COP film, and TAC film is more preferred, and a TAC film is even more preferred.

[0049] From the viewpoint of strength, the thickness of the transparent film substrate is preferably 5 μm or more, more preferably 10 μm or more, and even more preferably 20 μm or more. From the viewpoint of handleability, the thickness of the transparent film substrate is preferably 300 μm or less, and more preferably 200 μm or less.

[0050] One or both main surfaces of the transparent film substrate may be subjected to a surface modification treatment, such as a corona treatment, a plasma treatment, an ozone treatment, a primer treatment, a glow treatment, or a coupling agent treatment.

[0051] The total light transmittance (JIS K 7375-2008) of the transparent film substrate is preferably 80% or more, more preferably 90% or more, and even more preferably 95% or more and 100% or less, from the viewpoint of improving the transparency of the antireflection film.

[0052] [Hard coat layer] The hard coat layer is a layer that enhances the mechanical properties of the anti-reflection film, such as hardness and elastic modulus. The hard coat layer is made of, for example, a cured product of a curable resin composition (a composition for forming a hard coat layer). Examples of the curable resin contained in the curable resin composition include polyester resin, acrylic resin, urethane resin, urethane acrylate resin, amide resin, silicone resin, epoxy resin, and melamine resin. These curable resins may be used alone or in combination of two or more. From the viewpoint of enhancing the hardness of the hard coat layer, the curable resin is preferably one or more selected from the group consisting of acrylic resin and urethane acrylate resin, and more preferably a urethane acrylate resin.

[0053] Examples of the curable resin composition include an ultraviolet-curable resin composition and a thermosetting resin composition. From the viewpoint of improving the productivity of anti-reflection films, the curable resin composition is preferably an ultraviolet-curable resin composition. The ultraviolet-curable resin composition contains one or more selected from the group consisting of an ultraviolet-curable monomer, an ultraviolet-curable oligomer, and an ultraviolet-curable polymer. A specific example of the ultraviolet-curable resin composition is a composition for forming a hard coat layer described in JP 2016-179686 A.

[0054] The curable resin composition may also contain particles having a number-average primary particle diameter of 0.5 μm or more (hereinafter, sometimes referred to as "microparticles"). That is, the hard coat layer may contain microparticles. Blending microparticles into the curable resin composition makes it possible to adjust the hardness, surface roughness, refractive index, and antiglare properties of the hard coat layer. In particular, in order to easily adjust the maximum height Rz of the main surface of the antifouling layer opposite the antireflection layer side to 0.40 μm or more, it is preferable that the hard coat layer contain microparticles. Examples of microparticles include metal (or semi-metal) oxide particles, glass particles, and organic particles. Examples of materials for the metal (or semi-metal) oxide particles include silica, alumina, titania, zirconia, calcium oxide, tin oxide, indium oxide, cadmium oxide, and antimony oxide. Examples of materials for the organic particles include polymethyl methacrylate, polystyrene, polyurethane, (meth)acrylate compound-styrene copolymer, benzoguanamine, melamine, polymethylsilsesquioxane, and polycarbonate.

[0055] In order to easily adjust the antiglare properties of the hard coat layer, the number average primary particle diameter of the microparticles is preferably 1.0 μm or more and 5.0 μm or less, and more preferably 2.0 μm or more and 4.0 μm or less.

[0056] In order to easily adjust the antiglare properties of the hard coat layer, the amount of microparticles in the hard coat layer is preferably 3 parts by weight or more, and may be 5 parts by weight or more, 10 parts by weight or more, or 20 parts by weight or more, relative to 100 parts by weight of the curable resin. The upper limit of the amount of microparticles in the hard coat layer is, for example, 90 parts by weight, preferably 80 parts by weight, and may be 70 parts by weight, relative to 100 parts by weight of the curable resin.

[0057] The curable resin composition may also contain particles having a number average primary particle diameter of less than 0.5 μm (hereinafter, may be referred to as "nanoparticles"). When the hard coat layer is made of a cured product of the curable resin composition containing nanoparticles, fine irregularities are formed on the surface of the hard coat layer, which tends to improve adhesion between the hard coat layer and the layer formed thereon.

[0058] From the viewpoint of forming a fine uneven shape that contributes to improving adhesion, the number average primary particle diameter of the nanoparticles is preferably 20 nm or more and 80 nm or less, more preferably 25 nm or more and 70 nm or less, and even more preferably 30 nm or more and 60 nm or less.

[0059] As a material for the nanoparticles, inorganic oxides are preferred. Examples of inorganic oxides include oxides of metals (or semimetals) such as silicon oxide (silica), titanium oxide, aluminum oxide, zirconium oxide, niobium oxide, zinc oxide, tin oxide, cerium oxide, and magnesium oxide. The inorganic oxide may also be a composite oxide of multiple (semi)metals. Among the exemplified inorganic oxides, silicon oxide is preferred because of its high effect of improving adhesion. In other words, silicon oxide particles (silica particles) are preferred as nanoparticles. Functional groups such as acrylic groups and epoxy groups may be introduced onto the surfaces of inorganic oxide particles as nanoparticles in order to improve adhesion and affinity with resins.

[0060] The amount of nanoparticles in the hard coat layer is preferably 5 parts by weight or more, and may be 10 parts by weight or more, 20 parts by weight or more, or 30 parts by weight or more, relative to 100 parts by weight of the curable resin. If the amount of nanoparticles is 5 parts by weight or more, the adhesion to the layer formed on the hard coat layer can be further improved. The upper limit of the amount of nanoparticles in the hard coat layer is, for example, 90 parts by weight, preferably 80 parts by weight, and may be 70 parts by weight, relative to 100 parts by weight of the curable resin.

[0061] The curable resin composition (hard coat layer-forming composition) contains, for example, the above-mentioned curable resin and a polymerization initiator (e.g., a photopolymerization initiator), and optionally a solvent capable of dissolving or dispersing these components. In addition to the above components, the curable resin composition (hard coat layer-forming composition) may contain additives such as microparticles, nanoparticles, leveling agents, viscosity modifiers (thixotropic agents, thickeners, etc.), antistatic agents, antiblocking agents, dispersants, dispersion stabilizers, antioxidants, UV absorbers, antifoaming agents, surfactants, and lubricants.

[0062] By including a thixotropic agent in the composition for forming a hard coat layer, sedimentation of the microparticles is suppressed, and unevenness due to the microparticles tends to be uniformly formed on the surface of the hard coat layer. Examples of thixotropic agents include organic clay, oxidized polyolefin, and modified urea. Among these, organic clay such as smectite is preferred. The amount of the thixotropic agent to be added is preferably 0.3 parts by weight or more and 5 parts by weight or less per 100 parts by weight of the curable resin.

[0063] The surface of the antifouling layer reflects, for example, the uneven shape of the surface of the hard coat layer. Therefore, the maximum height Rz of the main surface of the antifouling layer opposite the antireflection layer side can be adjusted by, for example, changing at least one of the particle size of the microparticles in the composition for forming a hard coat layer, the amount of the microparticles in the composition for forming a hard coat layer, the type of thixotropic agent in the composition for forming a hard coat layer, and the amount of the thixotropic agent in the composition for forming a hard coat layer.

[0064] The thickness of the hard coat layer is preferably 1 μm or more, more preferably 2 μm or more, from the viewpoint of increasing the hardness of the hard coat layer, and is preferably 50 μm or less, more preferably 40 μm or less, even more preferably 35 μm or less, and still more preferably 30 μm or less, from the viewpoint of ensuring the flexibility of the antireflection film.

[0065] [Primer layer] To improve adhesion between the hard coat layer and the anti-reflection layer, a primer layer is preferably provided between the hard coat layer and the anti-reflection layer. Examples of materials for the primer layer include metals (or semi-metals) such as silicon, nickel, chromium, tin, gold, silver, platinum, zinc, titanium, indium, tungsten, aluminum, zirconium, and palladium; alloys of these metals (or semi-metals); and oxides, fluorides, sulfides, and nitrides of these metals (or semi-metals). The oxide constituting the primer layer may be a composite oxide such as indium tin oxide (ITO). Among these, inorganic oxides are preferred as materials for the primer layer, with silicon oxide, indium oxide, or ITO being more preferred, and SiOx (x<2) being even more preferred.

[0066] In order to ensure the light transmittance of the primer layer while improving the adhesion between the hard coat layer and the antireflection layer, the thickness of the primer layer is preferably 0.5 nm or more and 20 nm or less, more preferably 0.5 nm or more and 10 nm or less, and even more preferably 1.0 nm or more and 10 nm or less.

[0067] [Anti-reflection layer] The antireflection layer preferably consists of two or more thin films with different refractive indices. Generally, the optical film thickness (product of refractive index and thickness) of the thin films of the antireflection layer is adjusted so that the reversed phases of incident light and reflected light cancel each other out. By making the antireflection layer a multilayer laminate of two or more thin films with different refractive indices, the reflectance can be reduced over a wide wavelength range of visible light.

[0068] Examples of materials for the thin film constituting the antireflection layer include metal (or semimetal) oxides, nitrides, fluorides, etc. The antireflection layer is preferably an alternate laminate of high refractive index layers and low refractive index layers.

[0069] The high-refractive index layer has a refractive index of, for example, 1.9 or more, preferably 2.0 or more. Examples of materials for the high-refractive index layer include titanium oxide, niobium oxide (e.g., Nb2O5), zirconium oxide, tantalum oxide, zinc oxide, indium oxide, ITO, and antimony-doped tin oxide (ATO). Among these, at least one material selected from the group consisting of titanium oxide and niobium oxide is preferred. The low-refractive index layer has a refractive index of, for example, 1.6 or less, preferably 1.5 or less. Examples of materials for the low-refractive index layer include silicon oxide (e.g., SiO2), titanium nitride, magnesium fluoride, barium fluoride, calcium fluoride, hafnium fluoride, and lanthanum fluoride. Among these, silicon oxide is preferred. It is particularly preferred to alternately stack niobium oxide thin films as the high-refractive index layer and silicon oxide thin films as the low-refractive index layer. In addition to the low-refractive index layer and the high-refractive index layer, a medium-refractive index layer having a refractive index greater than 1.6 and less than 1.9 may be provided.

[0070] The thickness of each of the high-refractive-index layer and the low-refractive-index layer is preferably 10 nm to 200 nm, more preferably 10 nm to 150 nm. From the viewpoint of reducing reflectance, the thickness of the surface layer (low-refractive-index layer) of the antireflection layer on the antifouling layer side is preferably 15 nm to 200 nm, more preferably 20 nm to 200 nm, and even more preferably 20 nm to 150 nm. The thickness of each layer may be designed depending on the refractive index, layer structure, etc., so as to reduce the reflectance of visible light.

[0071] When the antireflection layer is a four-layer alternating laminate in which niobium oxide thin films as high refractive index layers and silicon oxide thin films as low refractive index layers are alternately laminated, the antireflection layer may have, from the hard coat layer side, a niobium oxide thin film having a thickness of 10 nm to 20 nm, a silicon oxide thin film having a thickness of 10 nm to 40 nm, a niobium oxide thin film having a thickness of 65 nm to 120 nm, and a silicon oxide thin film having a thickness of 60 nm to 100 nm, in this order.

[0072] In order to obtain an antireflection film having excellent flex resistance, the thickness of the antireflection layer is preferably 140 nm or more and 280 nm or less, more preferably 170 nm or more and 280 nm or less, even more preferably 180 nm or more and 260 nm or less, and even more preferably 190 nm or more and 250 nm or less. In this specification, the "thickness of the antireflection layer" refers to the sum of the thicknesses of the layers constituting the antireflection layer (total thickness).

[0073] [Anti-fouling layer] The antireflection film according to the first embodiment preferably includes an antifouling layer as the outermost layer, which can reduce the influence of contamination from the external environment (fingerprints, hand marks, dust, etc.) and facilitate the removal of contaminants adhering to the surface of the antireflection film, for example.

[0074] In order to prevent a decrease in the antireflection performance of the antireflection layer, it is preferable that the difference in refractive index between the antifouling layer and the outermost layer (silicon oxide layer) of the antireflection layer is small. The refractive index of the antifouling layer is preferably 1.6 or less, more preferably 1.55 or less.

[0075] The anti-fouling layer contains a fluorine-containing compound. As the fluorine-containing compound, a fluorine-containing compound having a terminal structure represented by the chemical formula CFO- (more specifically, CF3-O-) is preferred. A fluorine-containing compound having a terminal structure represented by the chemical formula CFO- can contribute to a lower refractive index while providing excellent anti-fouling properties. Among these, an alkoxysilane compound containing a perfluoropolyether skeleton is preferred as the fluorine-containing compound because it is capable of exhibiting excellent water repellency and high anti-fouling properties. Examples of alkoxysilane compounds containing a perfluoropolyether skeleton include compounds represented by the following general formula: CF3-(OCF2) m -(OC2F4) n -O-(CH2)3-Si(OCH3)3

[0076] In the above general formula, m represents an integer of 1 or more and 51 or less, and n represents an integer of 1 or more and 50 or less.

[0077] The fluorine-containing compound having a terminal structure represented by the chemical formula CFO- may be used alone or in combination of two or more. When the alkoxysilane compound is used as the fluorine-containing compound, the alkoxysilane compound may be present in the antifouling layer in a state in which the terminal alkoxy groups are reacted (crosslinked).

[0078] To obtain an anti-reflection film with excellent antifouling properties, the water contact angle of the main surface of the anti-fouling layer opposite the anti-reflection layer side (hereinafter sometimes simply referred to as the "anti-fouling layer surface") is preferably 110° or more, more preferably 115° or more. Furthermore, to ensure adhesion to a film (e.g., a surface protection film) to be attached to the anti-fouling layer surface, the water contact angle of the anti-fouling layer surface is preferably 125° or less. The water contact angle of the anti-fouling layer surface can be measured by the same method as in the Examples described below or a method equivalent thereto. The water contact angle of the anti-fouling layer surface can be adjusted, for example, by changing at least one of the type and amount of the fluorine-containing compound used.

[0079] The thickness of the antifouling layer is, for example, 2 nm or more and 50 nm or less. The thicker the antifouling layer, the more improved the antifouling properties tend to be. On the other hand, in order to further suppress reflection of external light, the thickness of the antifouling layer is preferably 30 nm or less, more preferably 20 nm or less, and even more preferably 15 nm or less.

[0080] The maximum height Rz of the antifouling layer surface is 0.40 μm or more, and in order to further suppress the reflection of external light, it is preferably 0.45 μm or more, more preferably 0.50 μm or more, and even more preferably 0.55 μm or more. The method for measuring the maximum height Rz of the antifouling layer surface is the same as or similar to the method described in the Examples below.

[0081] Furthermore, electrostatic discharge may occur between a typical antireflection film and a user's charged fingers or the like. When electrostatic discharge occurs between the antireflection film and a user's fingers or the like, discharge marks may occur on the surface of the antireflection film (for example, the surface of the antifouling layer). These discharge marks tend to occur more significantly in antiglare antireflection films that have an uneven surface formed to suppress reflection of external light. Discharge marks occurring on an antireflection film cause reduced visibility of the display. In the first embodiment, in order to suppress the occurrence of discharge marks, the maximum height Rz of the antifouling layer surface is preferably 1.50 μm or less, more preferably 1.40 μm or less, even more preferably 1.30 μm or less, and even more preferably 1.20 μm or less.

[0082] [Preferred embodiment of anti-reflection film] In order to obtain an antireflection film that suppresses reflection of external light, has even better antifouling properties and high-temperature durability, and can further reduce the environmental impact, the antireflection film according to the first embodiment preferably satisfies the following condition 1, and more preferably satisfies the following condition 2. Condition 1: The surface composition ratio F / Si is 3.50 or more and 7.00 or less. Condition 2: The above condition 1 is satisfied, and the composition ratio F / Si at a depth of 10 nm is 0.01 or less.

[0083] <Second embodiment: Method for manufacturing anti-reflection film> Next, a method for producing an antireflection film according to a second embodiment of the present invention will be described. The method for producing an antireflection film according to the second embodiment is a suitable method for producing the antireflection film according to the first embodiment described above. Hereinafter, the description of the same content as that of the first embodiment described above may be omitted.

[0084] The method for producing an antireflection film according to the second embodiment includes steps Sa, Sb, Sc, and Sd. In step Sa, a transparent film substrate having a hard coat layer is prepared. In step Sb, the main surface of the hard coat layer opposite the transparent film substrate side is plasma-treated in the presence of oxygen gas. In step Sc, an antireflection layer is formed on the plasma-treated main surface. In step Sd, an antifouling layer is formed on the main surface of the antireflection layer opposite the hard coat layer side.

[0085] Step Sa may be a step of preparing a commercially available transparent film substrate having a hard coat layer, or may be a step of forming a hard coat layer on one main surface of a transparent film substrate (hard coat layer forming step).

[0086] Hereinafter, step Sb may be referred to as a "hard coat layer surface treatment step", step Sc may be referred to as an "anti-reflection layer forming step", and step Sd may be referred to as an "anti-fouling layer forming step".

[0087] The method for producing an antireflection film according to the second embodiment may further include other steps in addition to the steps described above, such as the primer layer forming step described below.

[0088] Hereinafter, each step included in an example of the second embodiment will be described.

[0089] [Hard coat layer formation process] The hard coat layer forming step is a step of forming a hard coat layer on one main surface of a transparent film substrate. For example, a curable resin composition (a composition for forming a hard coat layer) is applied to the transparent film substrate, and the solvent is removed and the resin is cured as needed, thereby forming a hard coat layer. The composition for forming a hard coat layer contains, for example, the above-mentioned curable resin and a polymerization initiator (e.g., a photopolymerization initiator), and, as needed, a solvent capable of dissolving or dispersing these components.

[0090] In addition to the above components, the composition for forming a hard coat layer may contain additives such as microparticles, nanoparticles, leveling agents, viscosity modifiers (thixotropic agents, thickeners, etc.), antistatic agents, antiblocking agents, dispersants, dispersion stabilizers, antioxidants, ultraviolet absorbers, antifoaming agents, surfactants, and lubricants.

[0091] The hard coat layer-forming composition can be applied by any suitable method, such as bar coating, roll coating, gravure coating, rod coating, slot orifice coating, curtain coating, fountain coating, or comma coating. The drying temperature of the coating film after application may be set appropriately depending on the composition of the hard coat layer-forming composition, and is, for example, 50°C or higher and 150°C or lower. When the resin component in the hard coat layer-forming composition is a thermosetting resin, the coating film is cured by heating. When the resin component in the hard coat layer-forming composition is a photocurable resin, the coating film is cured by irradiating it with active energy rays such as ultraviolet light. The integrated light intensity of the irradiated light is preferably 100 mJ / cm. 2 More than 500mJ / cm 2 The following is the result.

[0092] [Hard coat layer surface treatment process] In the surface treatment process of the hard coat layer, the main surface of the hard coat layer opposite the transparent film substrate is plasma-treated in the presence of oxygen gas. This plasma treatment causes the main surface of the hard coat layer to have an irregular shape. It is presumed that the irregular shape of the hard coat layer promotes columnar growth of the sputtered film formed on the hard coat layer, resulting in the formation of an anti-reflection layer with high moisture permeability. The moisture permeability of the anti-reflection layer can be adjusted, for example, by changing the plasma treatment conditions (more specifically, pressure, amount of oxygen gas introduced, effective power density, etc.).

[0093] In the plasma treatment, for example, oxygen gas is introduced into the apparatus while the main surface of the hard coat layer opposite the transparent film substrate is plasma treated. In this case, a gas other than oxygen gas (another gas) may be introduced together with the oxygen gas, or only oxygen gas may be introduced without introducing the other gas. The other gas is preferably a rare gas, more preferably argon gas. When introducing the other gas, in order to form an antireflection layer with higher moisture permeability, the volume ratio of the other gas to oxygen gas (other gas / oxygen gas) is preferably 1 / 99 or more and 99 / 1 or less, more preferably 1 / 99 or more and 97 / 3 or less.

[0094] When the plasma treatment is carried out, in order to obtain an antireflection layer with higher moisture permeability, the treatment is preferably carried out under pressure conditions of 0.1 Pa or more and 1.0 Pa or less, and more preferably under pressure conditions of 0.3 Pa or more and 0.8 Pa or less.

[0095] When performing the above plasma treatment, in order to obtain an anti-reflection layer with a higher moisture permeability, the effective power density in the plasma treatment should be 0.01 W·min / cm 2 ·m or more, and 0.02W·min / cm 2 ·m or more is more preferable, and 0.03W·min / cm 2 In order to suppress deformation of the transparent film substrate during manufacturing, the effective power density in the plasma treatment is preferably 0.60 W·min / cm or more. 2 ·m or less, and 0.55W·min / cm 2 ·m or less is more preferable, and 0.50W·min / cm 2 ·m or less is more preferable, and 0.45W·min / cm 2 ·m or less is even more preferable, and 0.40W·min / cm 2 It is particularly preferable that the effective power density is equal to or less than 1 / 2 m. Note that the effective power density is the power density (W / cm 2) divided by the film transport speed (m / min) using the roll-to-roll method. Even if the plasma output is the same, if the transport speed is high, the effective treatment power will decrease.

[0096] [Primer layer formation process] The primer layer forming step is a step of forming (depositing) a primer layer on the hard coat layer. The method for depositing the primer layer is not particularly limited, and may be either a wet coating method or a dry coating method. Dry coating methods such as vacuum deposition, CVD, and sputtering are preferred because they can form a thin film with a uniform thickness, and sputtering is more preferred. Furthermore, from the viewpoint of improving productivity, a method of depositing the primer layer using a roll-to-roll sputtering deposition device (roll-to-roll sputtering method) is preferred.

[0097] In the roll-to-roll sputtering method, a long film (e.g., a transparent film substrate on which a hard coat layer has been formed) is transported in the longitudinal direction (MD direction) while, for example, a primer layer and an anti-reflection layer are continuously formed. In the sputtering method, film formation is performed while an inert gas such as argon, and optionally a reactive gas such as oxygen, are introduced into the film formation chamber. When an oxide layer is formed as the primer layer, the oxide layer can be formed by sputtering using either an oxide target or reactive sputtering using a metal (or semi-metal) target.

[0098] Examples of power sources for performing the sputtering method include DC power sources, AC power sources, RF power sources, and MFAC power sources (AC power sources with a frequency band of several kHz to several MHz). The power density when performing the sputtering method is, for example, 0.1 W / cm. 2 More than 20W / cm 2 less than or equal to 1 W / cm 2 More than 15W / cm 2The surface temperature of the film-forming roll when sputtering is performed is, for example, −25° C. or higher and 25° C. or lower, and preferably −20° C. or higher and 0° C. or lower. The pressure in the film-forming chamber when sputtering is performed (film-forming pressure) is preferably 0.01 Pa or higher and 10.0 Pa or lower, more preferably 0.05 Pa or higher and 5.0 Pa or lower, and even more preferably 0.1 Pa or higher and 1.0 Pa or lower.

[0099] [Anti-reflection layer formation process] In the antireflection layer forming step, an antireflection layer is formed on the side of the hard coat layer opposite the transparent film substrate (e.g., the surface of the hard coat layer or the surface of the primer layer). The method for forming the antireflection layer is not particularly limited, and may be either a wet coating method or a dry coating method. Dry coating methods such as vacuum deposition, CVD, and sputtering are preferred because they can form thin films with a uniform thickness, with sputtering being more preferred. Furthermore, from the viewpoint of improving productivity, roll-to-roll sputtering is preferred as the method for forming the antireflection layer. When performing sputtering in the antireflection layer forming step, the film formation conditions can be appropriately set, for example, within the conditions described in the above-mentioned [Primer Layer Forming Step]. The above-mentioned composition ratio F / Si can be changed, for example, by adjusting the film formation pressure when forming the surface layer (silicon oxide layer) on the antifouling layer side of the antireflection layer. When the film formation pressure is high, the surface layer of the silicon oxide layer tends to become porous. In particular, when an antireflection layer is formed on a hard coat layer with an uneven surface (for example, a hard coat layer containing microparticles), if the deposition pressure is set high, the surface layer of the silicon oxide layer is likely to become porous. If the surface layer of the silicon oxide layer (the surface layer of the antireflection layer on the antifouling layer side) becomes porous, fluorine-containing compounds tend to penetrate from the surface layer to the inside of the antireflection layer in the antifouling layer formation step described below, and the composition ratio F / Si inside the antireflection layer tends to increase.

[0100] In order to easily adjust the composition ratio F / Si at a depth of 10 nm to 0.02 or less, the deposition pressure when depositing the surface layer (silicon oxide layer) on the antifouling layer side of the antireflection layer is preferably 0.1 Pa or more and 0.4 Pa or less, and more preferably 0.1 Pa or more and 0.3 Pa or less.

[0101] [Anti-fouling layer formation process] The antifouling layer formation process is a process of forming an antifouling layer on the side of the antireflection layer opposite the hard coat layer side. In the antifouling layer formation process, a fluorine-containing compound is used as a material to form the antifouling layer by a wet coating method (hereinafter sometimes referred to as the "wet method") or a dry coating method (hereinafter sometimes referred to as the "dry method").

[0102] The wet method includes forming a coating film by applying a fluorine-based coating liquid containing a fluorine-containing compound to the surface of the antireflection layer, and then heating and drying the coating film to form an antifouling layer. Examples of the dry method include vacuum deposition, sputtering, and CVD, with vacuum deposition being preferred. When forming the antifouling layer by vacuum deposition, the heating temperature of the material (evaporation source) is, for example, 200°C or higher and 300°C or lower.

[0103] In the antifouling layer forming step, a layer containing a fluorine-containing compound (fluorine-containing layer) may be formed on the antireflection layer by a wet method or a dry method, and then excess fluorine-containing compound (e.g., unfixed fluorine-containing compound) present on the surface of the fluorine-containing layer may be removed. By removing the excess fluorine-containing compound, poor appearance of the film (e.g., cloudiness) caused by the excess fluorine-containing compound can be suppressed.

[0104] As a method for removing the excess fluorine-containing compound, for example, a method can be adopted in which the adhesive surface of a protective film is attached to the formed fluorine-containing layer, and then the protective film is peeled off from the fluorine-containing layer to adhere the excess to the adhesive surface. In this way, the excess fluorine-containing compound present on the surface layer of the fluorine-containing layer is removed, and an antifouling layer with reduced appearance defects is obtained. [Example]

[0105] Examples of the present invention will be described below, but the present invention is not limited to the following examples.

[0106] <Preparation of Antireflection Film of Example 1> [Hard coat layer formation process] The mixture consisted of 40 parts by weight of ultraviolet-curable urethane acrylate ("NK Oligo UA-53H-80BK" manufactured by Shin-Nakamura Chemical Co., Ltd.), 60 parts by weight of ultraviolet-curable acrylate ("Viscoat #300" manufactured by Osaka Organic Chemical Industry Ltd.), 4.3 parts by weight of polymethylsilsesquioxane particles ("Tospearl 130ND" manufactured by Momentive Performance Materials, Inc., number-average primary particle diameter: 3.0 μm, refractive index: 1.42), 2.5 parts by weight of a thixotropic agent ("Sumecton SAN" manufactured by Kunimine Industries Co., Ltd., a synthetic smectite which is an organic clay), and a photopolymerization initiator (IGM 3.0 parts by weight of a leveling agent ("Omnirad907" manufactured by Resins Co., Ltd.) and 0.04 parts by weight of a leveling agent ("LE303" manufactured by Kyoeisha Chemical Co., Ltd.) were mixed and diluted with a toluene / cyclopentanone mixed solvent (weight ratio: 60 / 40) to obtain a composition for forming a hard coat layer with a solids concentration of 30% by weight. Next, the composition for forming a hard coat layer was applied to one main surface of a TAC film (thickness: 40 μm) as a transparent film substrate to form a coating film. Next, this coating film was dried by heating at a temperature of 100°C for 60 seconds, and then cured by ultraviolet irradiation. When irradiating with ultraviolet light, a high-pressure mercury lamp was used as the light source, ultraviolet light with a wavelength of 365 nm was used, and the cumulative light amount was 300 mJ / cm. 2 As a result, a hard coat layer with a thickness of 8.5 μm was formed on the TAC film.

[0107] [Hard coat layer surface treatment process] Next, the surface of the hard coat layer was plasma-treated using a roll-to-roll plasma treatment device while the TAC film with the hard coat layer formed thereon was transported in a vacuum atmosphere of 0.6 Pa. The plasma treatment was performed using a mixture of argon gas and oxygen gas (volume ratio: Ar / O2 = 95 / 5) at an effective power density of 0.34 W·min / cm. 2 This resulted in a laminate (hereinafter sometimes referred to as "optical film F1") comprising the TAC film and the plasma-treated hard coat layer.

[0108] Next, the primer layer forming process and the anti-reflection layer forming process will be described. In the primer layer forming process and the anti-reflection layer forming process, when forming (depositing) the oxide film, argon gas and oxygen gas were introduced into the film forming chamber. When forming (depositing) the oxide film, the pressure was kept constant by adjusting the amount of argon gas introduced and exhausted, and the amount of oxygen gas introduced was adjusted by plasma emission monitoring (PEM) control or impedance control so that the film formation mode was maintained in the transition region.

[0109] [Primer layer formation process] The optical film F1 obtained by the above procedure was introduced into a roll-to-roll sputtering deposition apparatus, and the deposition chamber was filled with 1×10 -4 The pressure was reduced to 1 Pa. Next, while transporting the optical film F1, the surface temperature of the film-forming roll was lowered to -8°C, and a 4 nm thick SiOx layer (x<2) was formed (deposited) as a primer layer on one main surface of the hard coat layer by reactive sputtering. A Si target was used as the target material for forming the primer layer. When depositing the film by reactive sputtering, the power source was set to an MFAC power source (frequency: 40 kHz), and the power density was set to 3 W / cm. 2 The pressure in the film formation chamber was set to 0.4 Pa.

[0110] [Anti-reflection layer formation process] Following the formation of the primer layer, a roll-to-roll sputtering deposition apparatus was used to transport the optical film F1 after the primer layer formation. The following layers were deposited on one main surface of the primer layer by reactive sputtering in this order: a first layer: a 12 nm-thick niobium oxide layer (refractive index: 2.33), a second layer: a 28 nm-thick silicon oxide layer (refractive index: 1.46), a third layer: a 100 nm-thick niobium oxide layer, and a fourth layer: an 85 nm-thick silicon oxide layer. This resulted in a four-layer antireflection layer (consisting of a first layer, a second layer, a third layer, and a fourth layer) on one main surface of the primer layer. In each of the depositions of the first to fourth layers, the surface temperature of the deposition roll was set to -8°C, and the power source was an MFAC power source (frequency: 40 kHz). In each of the depositions of the first and third layers, a Nb target was used, and the power density was 13 W / cm. 2 The pressure in the deposition chamber was set to 0.6 Pa. In addition, in the deposition of the second and fourth layers, a Si target was used and the power density was set to 8 W / cm. 2 The pressure in the film formation chamber was set to 0.2 Pa.

[0111] [Anti-fouling layer formation process] A dried and solidified coating agent ("SHIN-ETSU SUBELYN KY1903-1" manufactured by Shin-Etsu Chemical Co., Ltd.) was used as a vapor deposition source. The vapor deposition source was heated to 260°C, and a layer containing a fluorine-containing compound (fluorine-containing layer) was formed on the main surface of the anti-reflection layer opposite the primer layer by vacuum deposition (dry method). The active ingredient of the coating agent ("SHIN-ETSU SUBELYN KY1903-1" manufactured by Shin-Etsu Chemical Co., Ltd.) used was an alkoxysilane compound (fluorine-containing compound) containing a perfluoropolyether skeleton and having a terminal structure represented by the chemical formula CFO-. Next, a protective film ("RP300C" manufactured by Nitto Denko Corporation) was attached to the formed fluorine-containing layer and left for 24 hours. The protective film was then peeled off from the fluorine-containing layer to remove excess fluorine-containing compound present on the surface of the fluorine-containing layer. As a result, an antifouling layer having a thickness of 5 nm was formed on the main surface of the antireflection layer opposite to the primer layer side, and an antireflection film of Example 1 was obtained.

[0112] <Preparation of Antireflection Film of Example 2> An antireflection film of Example 2 was obtained by the same production method as in Example 1, except that in the surface treatment step of the hard coat layer, argon gas was not used but only oxygen gas was used.

[0113] <Preparation of Antireflection Film of Comparative Example 1> An antireflection film of Comparative Example 1 was obtained by the same production method as in Example 1, except that in the surface treatment step of the hard coat layer, oxygen gas was not used but only argon gas was used.

[0114] <Preparation of Antireflection Film of Comparative Example 2> The anti-reflection film of Comparative Example 2 was obtained by the same production method as in Example 1, except that in the surface treatment process of the hard coat layer, oxygen gas was not used but only argon gas was used, and in the anti-reflection layer formation process, the pressure in the film formation chamber when forming the silicon oxide layers (second layer and fourth layer) was changed to 0.5 Pa.

[0115] <Analysis and evaluation methods> Next, the analysis and evaluation methods for the obtained anti-reflection film will be described.

[0116] [XPS analysis] Each anti-reflection film obtained by the above procedure was cut into a 1 cm x 1 cm size to prepare a measurement sample. Next, using an X-ray photoelectron spectrometer (Shimadzu Corporation's "KRATOS ULTA2") equipped with an Ar ion gun, the measurement sample was etched from the antifouling layer side under the following conditions, and composition analysis of each layer in the thickness direction by XPS was performed, and the surface composition ratio F / Si and the composition ratio F / Si at a depth of 10 nm were calculated. The composition ratio F / Si was calculated using peaks corresponding to the binding energy of each element obtained from the wide scan spectrum.

[0117] (Analysis conditions) X-ray source: Monochrome AlKα X-ray focal spot size: 110 μmφ (10 mA, 150 W) Photoelectron take-off angle: 90° to the sample surface Charge neutralization conditions: Combined use of electron neutralization gun and Ar ion gun (neutralization mode) Bond energy correction: Peaks due to CC bonds are corrected to 285.0 eV Acceleration voltage of Ar ion gun: 10 kV Ar ion gun raster size: 1mm x 1mm Etching rate of Ar ion gun: 1.52 nm / min (SiO2 equivalent)

[0118] [Maximum height Rz of the antifouling layer surface] Each antireflection film obtained by the above procedure was cut into a size of 5 cm x 5 cm to prepare a measurement sample. Next, a 1.3 mm thick glass slide (MATSUNAMI Corporation's "MICRO SLIDE GLASS", 45 mm x 50 mm) was attached to the TAC film side of the measurement sample (the surface without the antireflection layer) via a 20 μm thick acrylic adhesive layer. Next, the surface shape of the antifouling layer of each measurement sample (specifically, the main surface opposite the antireflection layer) was measured in a certain direction using a stylus-type surface roughness tester (Kosaka Laboratory's "Surfcorder ET4000") equipped with a diamond tip (curvature radius R = 2 μm) at a scanning speed of 0.1 mm / s and a measurement length of 4 mm. The obtained measurement data was analyzed using a program attached to the measuring instrument, and the maximum height Rz was determined from the roughness curve obtained through a wide-band filter with a cutoff value of 0.8 mm in accordance with JIS B0601:2001.

[0119] [Water contact angle] Each antireflection film obtained by the above procedure was cut into a size of 5 cm x 5 cm to prepare a measurement sample. Next, a 1.3 mm thick glass slide ("MICRO SLIDE GLASS" manufactured by Matsunami Co., Ltd., 45 mm x 50 mm) was attached to the TAC film side of the measurement sample (the surface without the antireflection layer) via a 20 μm thick acrylic adhesive layer. Next, using a contact angle measuring device ("DMo-701" manufactured by Kyowa Interface Science Co., Ltd.), 5.0 μL of water was dropped onto the antifouling layer surface of the measurement sample (specifically, the main surface of the antifouling layer opposite the antireflection layer side). 2 seconds after the drop, the angle between the antifouling layer surface and the tangent line to the edge of the droplet was measured to obtain the water contact angle of the antifouling layer surface.

[0120] [Fingerprint wipeability] Each antireflection film obtained by the above procedure was cut into a 5 cm x 5 cm size to prepare an evaluation sample. Next, a 1.3 mm thick glass slide (MICRO SLIDE GLASS, manufactured by MATSUNAMI Co., Ltd., 45 mm x 50 mm) was attached to the TAC film side of the evaluation sample (the surface without the antireflection layer) via a 20 μm thick acrylic adhesive layer. A finger was then pressed against the antifouling layer surface of the evaluation sample (specifically, the main surface opposite the antireflection layer) for 3 seconds, and then gently removed. The fingerprints were then wiped off in one direction with a nonwoven fabric (BEMCOT M1, manufactured by Asahi Kasei Corporation). The antifouling layer surface after wiping with the nonwoven fabric was then observed under a microscope (5x magnification). A rating of A (excellent antifouling properties) was given if no stains were observed, and a rating of B (poor antifouling properties) was given if stains were observed.

[0121] [Moisture permeability] In accordance with Appendix B of JIS K7129:2008, the moisture permeability of each anti-reflection film obtained by the above procedure was measured in an atmosphere of a temperature of 60°C and a relative humidity of 90%, and the measured value was taken as the moisture permeability of each anti-reflection layer.

[0122] [High temperature durability] (Preparation of polarizing plate) The TAC film-side principal surface of the optical film F1 obtained by the above procedure was laminated to one principal surface of a separately prepared polarizer using a roll laminator. A separately prepared TAC film (thickness: 80 μm, refractive index: 1.49) was then laminated to the other principal surface of the polarizer using a roll laminator, and the laminate was then heated and dried in an oven to obtain a polarizing plate. The polarizer used was a polyvinyl alcohol (PVA) film with an average degree of polymerization of 2700 and a thickness of 75 μm, which was dyed with iodine and stretched six times its original size. The PVA polarizer and TAC film were bonded together using an adhesive consisting of an aqueous solution containing an acetoacetyl-containing polyvinyl alcohol resin (average degree of polymerization: 1200, saponification degree: 98.5 mol%, acetoacetylation degree: 5 mol%) and methylolmelamine in a weight ratio of 3:1.

[0123] (Preparation of polarizing plate with adhesive layer) A 38 μm-thick release liner (a PET film release-treated with a silicone-based release agent) was separately prepared, and an acrylic adhesive was applied to one main surface of the release liner, followed by drying for 2 minutes at a temperature of 120° C. to form an adhesive layer on one main surface of the release liner. The resulting adhesive layer was then bonded to the TAC film of the polarizing plate (specifically, the TAC film not in contact with the hard coat layer), to obtain a polarizing plate with an adhesive layer.

[0124] (Preparation of anti-reflection film with polarizer) Each antireflection film obtained by the above procedure was bonded to the above polarizing plate with a pressure-sensitive adhesive layer via a 12 μm-thick pressure-sensitive adhesive layer. Specifically, the hard coat layer of the polarizing plate with a pressure-sensitive adhesive layer was bonded to the TAC film of the antireflection film to obtain an antireflection film with a polarizer.

[0125] (heating test and appearance observation) Each polarizer-equipped antireflection film obtained by the above procedure was placed in a hot air oven at a temperature of 95°C and removed after 1000 hours (heating test). Next, a commercially available polarizing plate was placed on the backlight, and the polarizer-equipped antireflection film after the heating test was placed on top of it in a crossed Nicol position, and the presence or absence of any change in appearance of the polarizer-equipped antireflection film was confirmed visually. Films that showed no change in appearance before and after the heating test were rated A (excellent high-temperature durability), and films that showed a change in appearance before and after the heating test were rated B (not excellent high-temperature durability).

[0126] [Reflections] A 1 mm-thick black acrylic resin plate was attached to the TAC film-side main surface (non-antireflection layer surface) of each antireflection film obtained by the above procedure via a 20 μm-thick acrylic adhesive layer to obtain an evaluation sample. Next, a three-band fluorescent lamp was placed 50 cm directly above the antireflection film of the evaluation sample under an illuminance of 1000 Lx (equivalent to a typical office environment using a display). The surface of the antireflection film was then visually observed to confirm the degree of reflection of the fluorescent tube. In all of Example 1, Example 2, Comparative Example 1, and Comparative Example 2, reflection of the fluorescent tube was successfully suppressed.

[0127] <Evaluation results> Table 1 shows the type of gas used in the surface treatment process of the hard coat layer, the pressure in the deposition chamber when depositing the silicon oxide layers (second and fourth layers), the surface composition ratio F / Si, the composition ratio F / Si at a depth of 10 nm, the maximum height Rz of the antifouling layer surface, the water contact angle, the evaluation results of fingerprint wiping ability, the moisture permeability, and the evaluation results of high-temperature durability for Example 1, Example 2, Comparative Example 1, and Comparative Example 2.

[0128] [Table 1]

[0129] As shown in Table 1, in Examples 1 and 2, the maximum height Rz of the antifouling layer surface was 0.40 μm or more, the surface composition ratio F / Si was 3.00 or more, the composition ratio F / Si at a depth of 10 nm was 0.02 or less, and the moisture permeability was 20 g / m 2 -It was more than 24 hours.

[0130] As shown in Table 1, in Examples 1 and 2, the evaluation results for fingerprint wiping ability were A. Therefore, the antireflection films of Examples 1 and 2 were excellent in antifouling property. In Examples 1 and 2, the evaluation results for high-temperature durability were A. Therefore, the antireflection films of Examples 1 and 2 were excellent in high-temperature durability.

[0131] As shown in Table 1, in Comparative Example 1, the moisture permeability was 20 g / m 2 In Comparative Example 2, the composition ratio F / Si at a depth of 10 nm exceeded 0.02.

[0132] As shown in Table 1, the evaluation result of high-temperature durability in Comparative Example 1 was B. Therefore, the antireflection film of Comparative Example 1 was not excellent in high-temperature durability. The evaluation result of fingerprint wiping ability in Comparative Example 2 was B. Therefore, the antireflection film of Comparative Example 2 was not excellent in antifouling property.

[0133] The above results demonstrate that the present invention can provide an antireflection film that is excellent in antifouling properties and high-temperature durability. [Explanation of symbols]

[0134] 10, 20 Anti-reflective film 11 Transparent film substrate 12 Hard coat layer 13 Anti-reflection layer 14 Antifouling layer 19 Primer layer 21 adhesive layer

Claims

1. An antireflection film having a transparent film substrate, a hard coat layer, an antireflection layer, and an antifouling layer containing a fluorine-containing compound in this order, the antireflection layer and the antifouling layer are in contact with each other, a surface layer of the antireflection layer on the antifouling layer side is a thin film containing silicon oxide as a main component and having a thickness of 10 nm or more; a maximum height Rz of a main surface of the antifouling layer opposite to the antireflection layer side is 0.40 μm or more; a composition ratio of fluorine to silicon, F / Si, on the main surface of the antifouling layer is 3.00 or more; when the composition ratio F / Si in the thickness direction of the antifouling layer and the antireflection layer is measured by X-ray photoelectron spectroscopy while etching the antifouling layer and the antireflection layer, the composition ratio F / Si at a location at a depth of 10 nm from the main surface of the antifouling layer side of the antireflection layer is 0.02 or less, The moisture permeability of the antireflection layer is 20 g / m ２ -Anti-reflective film lasting for 24 hours or more.

2. The moisture permeability of the antireflection layer is 1000 g / m ２ The anti-reflection film according to claim 1, wherein the durability is 24 hours or less.

3. The anti-reflection film according to claim 1 , wherein the anti-reflection layer further comprises a high refractive index layer having a refractive index higher than that of the thin film containing silicon oxide as a main component.

4. The anti-reflection film according to claim 1 , wherein the hard coat layer contains particles having a number average primary particle diameter of 0.5 μm or more.

5. The anti-reflective film according to claim 1 , further comprising a primer layer disposed between the hard coat layer and the anti-reflective layer.

6. The anti-reflection film according to claim 1 , further comprising a pressure-sensitive adhesive layer disposed on the transparent film substrate on the side opposite to the hard coat layer side.

7. A method for producing the anti-reflection film according to claim 1, A step Sa of preparing a transparent film substrate having a hard coat layer; a step Sb of subjecting a main surface of the hard coat layer opposite to the transparent film substrate side to a plasma treatment in the presence of oxygen gas; a step Sc of forming an anti-reflection layer on the plasma-treated main surface side; and forming an antifouling layer on the main surface of the antireflection layer opposite to the hard coat layer side.

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