High-angle Anti-reflection porous film and paint for forming high-angle Anti-reflection porous film

Abstract

The present disclosure provides, inter alia: a novel high-angle anti-reflection porous film having lower surface glossiness in a high-angle region where the incidence angle and the reflection angle exceed 60°; and a novel high-angle anti-reflection laminate in which said high-angle anti-reflection porous film is provided on a substrate. A high-angle anti-reflection porous film according to the present disclosure has a film density of 50-650 kg / m3 and a BET specific surface area (according to JIS Z 8830:2013) of 0.40-1.20 m2 / g. The 85-degree specular glossiness of one surface of the high-angle anti-reflection porous film is preferably 0.0-0.8%.

Description

High-angle anti-reflection porous film and coating material for forming high-angle anti-reflection porous film

[0001] The present invention relates to a novel high-angle antireflection porous film having a low surface gloss on the high-angle side, and a coating material for forming the high-angle antireflection porous film.

[0002] In various optical devices such as single-lens reflex cameras, compact cameras, video cameras, optical sensors such as infrared sensors, and smartphones, low-gloss anti-reflection materials and light-blocking materials are used from the viewpoint of removing unnecessary incident light and reflected light and suppressing the occurrence of halation, lens flare, ghosting, etc., or from the viewpoint of suppressing deterioration of captured images and deterioration of sensing detection accuracy, etc.

[0003] Such low-gloss anti-reflection members and light-shielding members are provided in various locations on the components that make up various optical devices (e.g., housings, outer tubes, inner tubes, camera housings, camera barrels, lenses, prisms, lens barrels, lens base mounts, shutters, diaphragm members, light-shielding plates, light-shielding rings, lens units, camera modules, etc.), regardless of whether they are on the outer surface, inner surface, opening end surface, outer peripheral end surface, inner peripheral end surface, front surface, back surface, side surface, etc.

[0004] As a low-gloss anti-reflection member for use in this type of application, the present applicant has developed a low-gloss anti-reflection member made of a binder resin, carbon black, and a reflective coating having an average particle diameter D of 5 to 20 μm. ５０ has proposed a low-reflection film containing at least organic resin particles having the formula (see Patent Document 1).

[0005] Furthermore, as a highly designed black coating film, a spray-coated film has been proposed which is formed from a liquid composition containing at least (A) a resin component, (B) roughness-forming particles, which are (B1) inorganic small particles having a particle diameter (d1) of 0.05 μm or more and 0.4 μm or less and (B2) inorganic large particles having a particle diameter (d2) of 2 μm or more and 6 μm or less, and (C) a dilution solvent (see Patent Documents 2 and 3).

[0006] International Publication No. 2020 / 195693 Japanese Patent Application Laid-Open No. 2022-124706 Japanese Patent Application Laid-Open No. 2023-090032

[0007] In recent years, as various optical devices have become smaller and thinner, the adoption of optical elements of bending optical systems has been considered. Optical elements of bending optical systems use reflecting mirrors, prisms, etc. to bend the optical path in any direction several times, thereby enabling the overall device to be made smaller and thinner while still allowing the incorporation of, for example, a higher-magnification telephoto zoom lens. However, bending optical systems can cause light to be reflected at high angles due to the bending of the optical path. As a result, it has been found that the adverse effects of high-angle incident and reflected light, with angles of incidence and reflection exceeding 60°, which were previously largely ignored, become apparent.

[0008] In the technology described in Patent Document 1, the average particle diameter D ５０ The use of coarse organic resin particles having the above structure as an essential component and increasing the surface roughness (see the examples in Patent Document 1) attempts to disperse reflected light from the surface and reduce surface gloss, but such attempts have already reached their technical limits. Specifically, the technology described in Patent Document 1 only achieves a 75-degree specular gloss of 0.6% to 6.0% and an 85-degree specular gloss of 0.9% to 3.3%. Furthermore, the technologies described in Patent Documents 2 and 3 also use small particles having a particle diameter of 0.05 μm to 0.4 μm as essential components in addition to large inorganic particles having a particle diameter of 3 μm to 8 μm (see the examples in Patent Documents 2 and 3). However, this is intended to adjust the surface arrangement of the large particles (i.e., surface roughness) using the small particles, and is essentially no different from the technology described in Patent Document 1. Therefore, the technologies described in Patent Documents 2 and 3 can be understood to achieve the same 75-degree specular gloss and 85-degree specular gloss as Patent Document 1, and there are technical limits to reducing surface gloss.

[0009] On the other hand, the present inventors have investigated a method for reducing the surface gloss at high angles without increasing the surface roughness by using coarse particles, but have found that it is difficult to realize an anti-reflection film with reduced surface gloss simply by not using coarse particles. ５０The surface reflectance and surface gloss of a commercially available light-shielding film (KIMOTO Co., Ltd., product name: Carbon Feather X6B) that does not use coarse particles of 2 μm or more and 20 μm or less are as follows.

[0010] The present invention has been made in view of the above-mentioned problems. That is, an object of the present invention is to provide a novel high-angle antireflection porous film having a lower surface gloss in the high-angle region where the angle of incidence and the angle of reflection exceed 60°, and a novel high-angle antireflection laminate in which the high-angle antireflection porous film is provided on a substrate. Another object of the present invention is to provide a novel coating material or the like capable of forming such a high-angle antireflection porous film.

[0011] As a result of extensive research to solve the above problems, the inventors have discovered that a porous film having a predetermined porous structure functions as a high-angle anti-reflection film with low surface gloss in the high-angle region, and have thus completed the present invention.

[0012] That is, the present invention provides the following various specific embodiments: [1] 50 to 650 kg / m ３ and a film density of 0.40 to 1.20 m ２ / g BET specific surface area (JIS Z8830 (2013) compliant).

[0013] [2] The high-angle anti-reflection porous film according to [1], wherein the 85-degree specular gloss of one surface is 0.0% or more and 0.8% or less.

[0014] [3] The high-angle anti-reflection porous film according to [1] or [2], which is a porous film in which a plurality of fine particles are aggregated and bound.

[0015] [4] The high-angle anti-reflection porous film according to [3], wherein the fine particles are spray-dried fine particles.

[0016] [5] The high-angle anti-reflection porous film according to any one of [1] to [4], wherein the porous film contains a matting agent.

[0017] [6] The high-angle antireflection porous film according to any one of [1] to [5], wherein the porous film contains a binder resin.

[0018] [7] The high-angle antireflection porous film according to any one of [1] to [6], further comprising a light-blocking agent.

[0019] [8] The high-angle anti-reflection porous film according to [7], wherein the light-shielding agent contains carbon black.

[0020] [9] A high-angle anti-reflection laminate comprising a substrate and the high-angle anti-reflection porous film according to any one of [1] to [8] provided on at least one surface of the substrate.

[0021]

[10] A coating material for forming a high-angle anti-reflection porous film, comprising at least a binder resin, a matting agent, and a solvent, wherein the matting agent is contained in an amount of 100 to 1000 parts by mass in terms of solid content relative to 100 parts by mass of the solid content of the binder resin.

[0022]

[11] The coating material for forming a high-angle anti-reflection porous film according to

[10] , further containing a light-shielding agent.

[0023]

[12] The coating material for forming a high-angle anti-reflection porous film according to

[11] , wherein the light-shielding agent contains carbon black.

[0024]

[13] The coating material for forming a high-angle anti-reflection porous film according to any one of

[10] to

[12] , which is for spray-drying coating.

[0025] According to the present invention, it is possible to realize a novel high-angle antireflection porous film having a lower surface gloss in the high-angle region where the incident angle and reflection angle exceed 60°, and a high-angle antireflection laminate using the same, and to provide a new material that has not existed before. The high-angle antireflection porous film can be suitably used as an antireflection material having a low surface gloss in the high-angle region, and can be particularly suitably used as an antireflection material for a bending optical system where the adverse effects of incident light and reflected light on the high-angle side exceeding 60° become apparent.

[0026] 1 is a cross-sectional SEM photograph showing the high-angle antireflection laminate of Example 3 in which a high-angle antireflection porous film is provided on the lower surface of a substrate. 2 is a cross-sectional SEM photograph showing the antireflection film of Example 8 of the prior art.

[0027] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. Unless otherwise specified, positional relationships such as up, down, left, and right are based on the positional relationships shown in the drawings. Furthermore, the dimensional ratios of the drawings are not limited to those shown. However, the following embodiments are examples for explaining the present invention, and the present invention is not limited to these. In this specification, for example, the notation of a numerical range such as "1 to 100" includes both the lower limit "1" and the upper limit "100". The same applies to notations of other numerical ranges.

[0028] The high-angle antireflection porous film according to one aspect of this embodiment has a resistance of 50 to 650 kg / m ３ and a film density of 0.40 to 1.20 m ２ / g.

[0029] In addition, the high-angle antireflection laminate of one aspect of this embodiment is characterized by comprising a substrate and the high-angle antireflection porous film provided on at least one side of this substrate.That is, this high-angle antireflection laminate has a laminate structure (two-layer structure) in which the high-angle antireflection porous film and the substrate are arranged at least in this order.In this laminate structure, the high-angle antireflection porous film is arranged on the outermost surface of the front side, and the high-angle antireflection porous film is arranged in an exposed state on the outermost surface of the front side.

[0030] Here, in this specification, "provided on one (other) surface side of" means not only the embodiment in which the high-angle antireflection porous film is directly placed on the surface (for example, the upper surface or the lower surface) of the substrate as in this embodiment, but also the embodiment in which an optional layer (for example, a primer layer, an adhesive layer, etc.) not shown is interposed between the upper surface of the substrate and the high-angle antireflection porous film, and the high-angle antireflection porous film is arranged at a distance from the substrate.Furthermore, the laminated structure comprising at least the high-angle antireflection porous film and the substrate means not only the structure in which only the high-angle antireflection porous film is directly laminated on the substrate, but also the structure in which the optional layer as described above is further provided between the layers of the two-layer structure.

[0031] The type of substrate is not particularly limited as long as it can support the high-angle antireflection porous film. The substrate may be, for example, an object having a hard surface made of glass, resin, metal, ceramics, wood, etc. From the viewpoint of antireflection in the high-angle range of optical elements, the substrate may be a component constituting various optical devices such as a housing, an outer tube, an inner tube, a camera housing, a camera barrel, a lens, a prism, a lens barrel, a lens base mount, a shutter, an aperture member, a light-shielding plate, a light-shielding ring, a lens unit, a camera module, etc. Furthermore, from the viewpoint of antireflection in the high-angle range of optical elements of a bending optical system, the substrate may be a material selected from the group consisting of general optical glass, low-thermal expansion glass, borosilicate glass, quartz, Si, CaF ２ The substrate may be an optical prism made of various plastics, etc. Examples of the optical prism include a rectangular prism, a corner cube prism, a deflection prism, a Dove prism, a pentaprism, a tetraprism, a Porro prism, a roof prism, a rhombic prism, a Dove prism, and a beam splitter. The substrate may be a synthetic resin film such as a polyester film, an ABS (acrylonitrile-butadiene-styrene) film, a polyimide film, a polyamide film, a polyamideimide film, a polystyrene film, or a polycarbonate film. These may be used alone or in combination of two or more.

[0032] The size and thickness of the substrate can be appropriately set depending on the required performance and application, and are not particularly limited. For example, any part of the components constituting the various optical devices described above can be used as the substrate. Note that, from the viewpoint of improving adhesion to the high-angle antireflection porous film, various known surface treatments such as anchor treatment and corona treatment can be performed on the surface of the substrate as needed. Furthermore, the appearance of the substrate can be appropriately set depending on the required performance and application, and is not particularly limited. The substrate may be transparent, translucent, or opaque, and is not particularly limited. However, for optical element applications such as lenses and prisms, the substrate preferably has light-transmitting properties, and for light-shielding applications such as housings, external cylinders, camera housings, camera barrels, shutters, diaphragm members, light-shielding plates, and light-shielding rings, the substrate preferably has light-shielding properties.

[0033] High-angle anti-reflection porous film: 50 to 650 kg / m ３ and a film density of 0.40 to 1.20 m ２ / g BET specific surface area. By having such a predetermined porous structure, it is possible to realize a high-angle anti-reflection porous film and a high-angle anti-reflection laminate with low surface gloss in the high-angle region where the angle of incidence and the angle of reflection exceed 60°. The reason for this effect is unclear, but the following is presumed. That is, a porous film composed of lightweight, fine pores with a low film density and a large specific surface area has a structure with many fine gaps (voids) in the film, and when light is incident on these voids, the light is reflected or scattered into the voids, resulting in attenuation of the light. This action of confining light within the film efficiently suppresses light reflection in the high-angle region. By adjusting the size of the voids, this effect can be expected at all angles, from low angles to high angles, and it is presumed to be particularly useful for light reflection in the high-angle region, where reflection is difficult to suppress.

[0034] The film density of the high-angle anti-reflection porous film is 50 to 650 kg / m ３ is preferable, and more preferably 50 to 600 kg / m ３ and more preferably 50 to 550 kg / m ３ and particularly preferably 50 to 500 kg / m ３ and most preferably 70 to 450 kg / m ３ In this specification, the film density of a high-angle antireflection porous film is a value calculated from the mass and volume of the film, and can be calculated, for example, by the following procedure. In the case of only a high-angle antireflection porous film, the high-angle antireflection porous film is cut into 10 cm squares, weighed to determine the mass of the sample, and divided by the film thickness to determine the film density (kg / m ３) is calculated. In addition, when a high-angle antireflection porous film is formed on a substrate, the substrate alone and a laminate in which a high-angle antireflection porous film is formed on the substrate are prepared, and each is cut into a 10 cm square to obtain a substrate sample and a laminate sample, respectively. Thereafter, the substrate sample and the laminate sample are weighed, and the mass of the substrate sample and the mass of the laminate sample are determined. Then, the mass of the high-angle antireflection porous film alone is calculated by subtracting the mass of the substrate sample from the mass of the laminate sample, and this is divided by the film thickness to obtain the film density (kg / m) of the high-angle antireflection porous film. ３ The shape and size of the sample are examples and may vary depending on the size and shape of the coating film.

[0035] The BET specific surface area of ​​the high-angle anti-reflection porous film is 0.40 to 1.20 m ２ / g, and more preferably 0.40 to 1.10 m ２ / g, and more preferably 0.40 to 1.00 m ２ / g, and particularly preferably 0.40 to 0.90 m ２ / g, and most preferably 0.45 to 0.90 m ２ In this specification, the BET specific surface area of ​​the high-angle antireflection porous film is a value (m ２ In this case, an appropriate gas can be selected depending on the sample for measurement, but in this example, the measurement was carried out using krypton (Kr) gas.

[0036] It should be noted that the thickness of high-angle antireflection porous film can be suitably set according to required performance and use, and is not particularly limited.From the viewpoint of the balance between light weight and thin film, the thickness of high-angle antireflection porous film is preferably 0.1 μ m or more, more preferably 0.2 μ m or more, even more preferably 0.5 μ m or more, particularly preferably 1.0 μ m or more, most preferably 4.0 μ m or more, and the upper limit side is preferably 40 μ m or less, more preferably 35 μ m or less, even more preferably 30 μ m or less, particularly preferably 25 μ m or less.Here, the high-angle antireflection porous film with porous structure often has surface unevenness, so the thickness of high-angle antireflection porous film is measured at any 10 points and is taken as the average value.

[0037] Table 2 shows the correlation between the film density and BET specific surface area of ​​the antireflection porous film and the specular gloss. ５０ and 0.1 to 35% by mass of a matting agent (silica particles) having an average particle diameter D ５０ High-angle antireflection laminates (Examples 1 to 7) in which a high-angle antireflection porous film is formed by a spray drying method (spray coating method) using a coating liquid containing a light-shielding agent (carbon black) having an average particle diameter D of 25 nm, 0.1 to 10% by mass of a curing agent and 0.001 to 1% by mass of a leveling agent, which are blended as needed, and a required amount of solvent, and high-angle antireflection laminates (Examples 1 to 7) in which a high-angle antireflection porous film is formed by a spray drying method (spray coating method) using a coating liquid containing a light-shielding agent (carbon black) having an average particle diameter D of 30 to 45% by mass ５０ and 20 to 45% by mass of a matting agent (irregular shaped silica particles) having an average particle diameter D ５０The figure also shows a conventional antireflection laminate (Example 8) in which an antireflection film was formed by a spray drying method (spray coating method) using a coating solution containing a light-shielding agent (carbon black) having a particle size of 25 nm, 0.1 to 10% by mass of a curing agent and 0.001 to 1% by mass of a leveling agent, which are blended as needed, and a required amount of solvent. Also shown is a cross-sectional SEM photograph of the high-angle antireflection laminate of Example 3, and Figure 2 shows a cross-sectional SEM photograph of the antireflection laminate of Example 8. The high-angle antireflection porous films of Examples 1 to 7, which satisfy the above-mentioned film density and BET specific surface area, have low 75-degree specular gloss and 85-degree specular gloss. On the other hand, the high-angle antireflection porous film of Example 8 of the conventional technology, which does not satisfy the film density and BET specific surface area, has high 75-degree specular gloss and 85-degree specular gloss.

[0038] The film density and BET specific surface area of ​​the high-angle antireflection porous film can be controlled by any method. For example, increasing the content of the binder resin used tends to increase the film density and decrease the BET specific surface area. Also, decreasing the content of the binder resin tends to decrease the film density and increase the BET specific surface area. On the other hand, in the case of bulk coating to form a high-angle antireflection porous film using a brush, roll coater, applicator, etc., the film density tends to increase and the BET specific surface area tends to decrease. On the other hand, in the case of forming a high-angle antireflection porous film by spray coating with a paint mist formed by a spray drying method (spray coating method), the paint is sprayed from a spray nozzle, etc., in the form of many minute droplets in the form of fine particles, and these many minute droplets are dried to the extent that they can maintain their particulate shape until they hit the substrate, and many granular deposited particles hit the substrate. Therefore, when a film is formed by the spray drying method, the film structure is formed by stacking granular coated particles, which tends to result in a lower film density and a larger BET specific surface area.Furthermore, when a film is formed by the spray drying method, by using multi-stage coating rather than batch coating, the film structure is formed by further stacking granular coated particles, which tends to result in a lower film density and a larger BET specific surface area.In this case, the higher the number of layers, the more voids tend to be formed, which tends to result in a lower film density and a larger BET specific surface area.In addition, when a solvent with relatively high volatility is used, the BET specific surface area tends to be larger, and when a solvent with relatively low volatility is used, the BET specific surface area tends to be smaller.

[0039] As the material for forming the high-angle antireflection porous film, any material known in the art can be used according to the desired film density and BET specific surface area, and its type is not particularly limited.For example, the high-angle antireflection porous film of this embodiment can be obtained by preparing a coating liquid containing a binder resin and any optional components (light-shielding agent, various additives) that are blended as needed in a solvent, applying this coating liquid to the surface of a substrate, drying, and then, if necessary, carrying out heat treatment, pressure treatment, etc., to form a high-angle antireflection porous film on the surface of the substrate.In addition, for example, a coating liquid containing a binder resin, a matting agent, and any optional components (light-shielding agent, various additives) that are blended as needed in a solvent can be prepared, applying this coating liquid to the surface of a substrate, drying, and then, if necessary, carrying out heat treatment, pressure treatment, etc., to form a high-angle antireflection porous film on the surface of the substrate.Hereinafter, each component will be described in detail.

[0040] The binder resin may be any known resin in the art depending on the required performance and application, and the type is not particularly limited. Specific examples include thermoplastic resins or thermosetting resins such as poly(meth)acrylic acid resins, polyester resins, polyvinyl acetate resins, polyvinyl chloride resins, polyvinyl butyral resins, cellulose resins, polystyrene / polybutadiene resins, polyurethane resins, alkyd resins, acrylic resins, unsaturated polyester resins, epoxy ester resins, epoxy resins, epoxy acrylate resins, urethane acrylate resins, polyester acrylate resins, polyether acrylate resins, phenolic resins, melamine resins, urea resins, and diallyl phthalate resins. Thermoplastic elastomers, thermosetting elastomers, ultraviolet-curable resins, and electron beam-curable resins may also be used. The binder resins may be used alone or in combination of two or more.

[0041] The content (total amount) of the binder resin in the high-angle antireflection porous film is not particularly limited. In one embodiment, from the viewpoint of realizing the film density and BET specific surface area in the above-mentioned preferred ranges, the content (total amount) of the binder resin may be 1 to 65 mass%, 5 to 55 mass%, 15 to 50 mass%, or 20 to 45 mass%, calculated as solid content relative to the total amount of the high-angle antireflection porous film.

[0042] As the matting agent, those known in the art can be used depending on the required performance and application, and the type thereof is not particularly limited. Specific examples include kaolin, calcined kaolin, calcined clay, uncalcined clay, silica (e.g., natural silica, fused silica, amorphous silica, hollow silica, wet silica, synthetic silica, aerosil, etc.), aluminum compounds (e.g., boehmite, aluminum hydroxide, alumina, hydrotalcite, aluminum borate, aluminum nitride, etc.), magnesium compounds (e.g., magnesium aluminometasilicate, magnesium carbonate, magnesium oxide, magnesium hydroxide, etc.), calcium compounds (e.g., calcium carbonate, calcium hydroxide, calcium sulfate, calcium sulfite, etc.), and the like. Examples of suitable inorganic particles include inorganic particles such as molybdenum compounds (e.g., molybdenum oxide, zinc molybdate, etc.), molybdenum compounds (e.g., molybdenum oxide, zinc molybdate, etc.), talc (e.g., natural talc, calcined talc, etc.), mica, titanium oxide, zinc oxide, zirconium oxide, barium sulfate, zinc borate, barium metaborate, sodium borate, boron nitride, aggregated boron nitride, silicon nitride, carbon nitride, strontium titanate, barium titanate, and stannates such as zinc stannate; and organic resin particles such as polymethyl methacrylate, polystyrene, polyester, polyurethane, and rubber. Here, black particles such as magnetite black, copper-iron-manganese black, titanium black, carbon black, and aniline black are considered to be light-shielding agents, as will be described later, but are not considered to be matting agents. Furthermore, with regard to particle components (e.g., black resin particles) in which a matting agent and a light-blocking agent are combined, when the light-blocking agent component is less than 50% by mass, it is treated as a matting agent, and when the light-blocking agent component is 50% by mass or more, it is treated as a light-blocking agent. Note that the matting agent may be used alone or in combination of two or more.

[0043] From the viewpoint of realizing the film density and BET specific surface area within the above-mentioned preferred ranges and reducing the surface gloss in the high angle region where the incident angle and the reflection angle exceed 60°, it is preferable to use a matting agent having a relatively smaller particle diameter than conventional matting agents. ５０In one embodiment, the average particle diameter D of the matting agent ５０ In one embodiment, the average particle diameter D of the matting agent may be 1.0 to 10.0 μm, or 3.0 to 8.2 μm. ５０ The average particle diameter D in this specification may be 0.6 to 1.8 μm, 0.7 to 1.7 μm, 0.8 to 1.6 μm, or 0.9 to 1.5 μm. ５０ is the volume-based median diameter (D) measured by a laser diffraction particle size distribution analyzer (e.g., Shimadzu Corporation: SALD-7000, etc.). ５０ ) means

[0044] The content (total amount) of the matting agent in the high-angle antireflection porous film is not particularly limited, but from the viewpoint of realizing the film density and BET specific surface area in the above-mentioned preferred ranges, the content (total amount) of the matting agent may be 100 to 1000 parts by mass, calculated as solid content, relative to 100 parts by mass of the solid content of the binder resin. Also, in one embodiment, the content (total amount) of the matting agent may be 150 parts by mass or more, 300 parts by mass or more, or 500 parts by mass or more, and may be 1000 parts by mass or less, 800 parts by mass or less, or 700 parts by mass or less, calculated as solid content, relative to 100 parts by mass of the solid content of the binder resin.

[0045] Furthermore, the content (total amount) of the matting agent in the high-angle antireflection porous film is not particularly limited, but from the viewpoint of realizing the film density and BET specific surface area within the above-mentioned preferred numerical ranges, the content (total amount) of the matting agent may be preferably 63 mass% or more, more preferably 70 mass% or more, even more preferably 80 mass% or more, relative to the total amount (100 mass%) of all solid contents of the composition, and may be preferably 95 mass% or less, more preferably 93 mass% or less, even more preferably 90 mass% or less.

[0046] The high-angle antireflection porous film may contain a light-shielding agent. By using the light-shielding agent, the surface glossiness can be further reduced, and the optical density can be increased to impart light-shielding properties, so that the high-angle antireflection porous film can also function as a light-shielding film.

[0047] As the light-blocking agent, any known agent in the art can be used, and the type is not particularly limited. For example, black particles are preferably used as the light-blocking agent. Examples of black particles include, but are not limited to, black resin particles, magnetite black, copper-iron-manganese black, titanium black, carbon black, and aniline black. Among these, black resin particles, titanium black, carbon black, and aniline black are preferred, and carbon black and aniline black are more preferred.

[0048] Carbon black includes oil furnace black, lamp black, channel black, gas furnace black, acetylene black, thermal black, ketjen black, and the like, which are produced by various known methods, but the type is not particularly limited. Conductive carbon black is particularly preferred from the viewpoint of imparting conductivity to the high-angle antireflection porous film and preventing static charging. Carbon black has a long history, and various grades of carbon black and carbon black dispersions are commercially available from, for example, Mitsubishi Chemical Corporation, Asahi Carbon Co., Ltd., Mikuni Color Co., Ltd., Resino Color Industries Co., Ltd., Cabot Corporation, and DEGUSSA. An appropriate material may be selected from these depending on the required performance and application. These light-shielding agents may be used alone or in combination of two or more.

[0049] The particle size of the light-shielding agent is not particularly limited and can be appropriately set depending on the required performance, etc. In one embodiment, the particle size of the light-shielding agent is preferably smaller than that of the matting agent. For example, the average particle diameter D ５０ In one embodiment, the average particle diameter D ５０ In a preferred embodiment, the average particle diameter D of the matting agent is 0.03 to 0.28 μm, or 0.05 to 0.25 μm. ５０ is 0.6 to 14.0 μm, and the average particle diameter D ５０ is 0.01 to 0.30 μm.

[0050] When a light-shielding agent is used, the content (total amount) of the light-shielding agent may be 1 to 55% by mass relative to the total amount of the high-angle antireflection porous film, from the viewpoints of dispersibility, film-forming property, handleability, light-shielding property, matte property, etc., and from the viewpoint of the blending balance with the binder resin and matting agent. In one embodiment, the content (total amount) of the light-shielding agent may be 5 to 45% by mass, 7 to 40% by mass, or 7 to 30% by mass relative to the total amount of the high-angle antireflection porous film.

[0051] The high-angle antireflection porous film may contain various additives known in the art. Specific examples thereof include, but are not limited to, lubricants, conductive agents, flame retardants, antibacterial agents, antifungal agents, antioxidants, plasticizers, resin curing agents, curing accelerators, leveling agents, flow control agents, antifoaming agents, dispersants, and the like. Examples of lubricants include hydrocarbon-based lubricants such as polyethylene, paraffin, and wax; fatty acid-based lubricants such as stearic acid and 12-hydroxystearic acid; amide-based lubricants such as stearic acid amide, oleic acid amide, and erucic acid amide; ester-based lubricants such as butyl stearate and stearic acid monoglyceride; alcohol-based lubricants; solid lubricants such as metal soaps, talc, and molybdenum disulfide; and fluororesin particles such as silicone resin particles, polytetrafluoroethylene wax, and polyvinylidene fluoride. Among these, organic lubricants are particularly preferred. Furthermore, when an ultraviolet-curable resin or an electron beam-curable resin is used as the binder resin, a sensitizer or an ultraviolet absorber, such as n-butylamine, triethylamine, or tri-n-butylphosphine, may be used. These may be used alone or in combination of two or more. The content ratio of these is not particularly limited. Each may be 0.01 to 5 mass% in terms of solid content relative to the total resin components contained in the high-angle antireflection porous film. From the viewpoint of realizing the film density and BET specific surface area within the above-mentioned preferred numerical ranges and reducing the surface gloss in the high-angle region where the angle of incidence and the angle of reflection exceed 60°, the high-angle antireflection porous film contains, in addition to the binder resin, matting agent, and light-shielding agent, an average particle diameter D ５０ It is preferable that the particle size does not include large particles having a size of 2.0 μm or more, preferably 20 μm or less.

[0052] When a high-angle antireflection porous film is used as the light-shielding member, the optical density (OD) of the high-angle antireflection porous film may be 0.5 or more from the viewpoint of providing high light-shielding properties. In one aspect, the optical density (OD) of the high-angle antireflection porous film may be 1.0 or more, 1.7 or more, or 2.0 or more. In this specification, the optical density (OD) is a value obtained by measurement in accordance with ISO 5-2 using an optical densitometer (X-Rite 361T: X-Rite Corporation) and an ortho filter.

[0053] As described above, the surface reflectance of the high-angle antireflection laminate and the high-angle antireflection porous film of this embodiment can be such that the 70-degree regular reflectance of the surface on the high-angle antireflection porous film side (in this embodiment, the surface of the high-angle antireflection porous film) is 0.0% or more and 2.5% or less (wavelength 550 nm) from the viewpoint of reducing the surface glossiness in the high-angle region where the incident angle and reflection angle exceed 60 °. From the viewpoint of realizing higher matte properties and low surface reflection, the 70-degree regular reflectance can be 0.0% or more and 2.0% or less (wavelength 550 nm), 0.0% or more and 1.5% or less (wavelength 550 nm), 0.0% or more and 1.0% or less (wavelength 550 nm), or 0.0% or more and 0.5% or less (wavelength 550 nm). In this specification, the 70-degree regular reflectance is a value obtained by measuring the regular reflectance (specular reflectance) (%) of the surface of a high-angle anti-reflection porous film at an incident and receiving angle of 70° for light with a wavelength of 550 nm using a spectrophotometer (SolidSpec-3700: Shimadzu Corporation).

[0054] Furthermore, as described above, the specular gloss of the anti-reflection laminate 100 and the high-angle anti-reflection porous film of this embodiment is such that, from the viewpoint of reducing the surface gloss in the high-angle region where the angle of incidence and the angle of reflection exceed 60°, the specular gloss of the surface on the high-angle anti-reflection porous film side (the surface of the high-angle anti-reflection porous film in this embodiment) can be 0.0% or more and 1.2% or less at 75° and 0.0% or more and 0.8% or less at 85°. In one aspect, the 75° specular gloss may be 0.0% or more and 1.0% or less, 0.0% or more and 0.7% or less, or 0.0% or more and 0.5% or less. In another aspect, the 85° specular gloss may be 0.0% or more and 0.7% or less, or 0.0% or more and 0.6% or less. In this specification, the specular glossiness is a value obtained by measuring the glossiness (specular glossiness) (%) of the surface of a high-angle anti-reflection porous film at each of the specified incident and receiving angles (20°, 45°, 60°, 75°, 85°) using a digital variable-angle glossmeter (Gloss Meter VG7000: Nippon Denshoku Co., Ltd.) in accordance with JIS-Z8741:1997.

[0055] When a high-angle antireflection laminate is used as a light-shielding member, the high-angle antireflection laminate may have an overall optical density (OD) of 0.5 or more, in order to provide high light-shielding properties as a light-shielding member. In one embodiment, the high-angle antireflection laminate may have an overall optical density (OD) of 1.0 or more, 1.7 or more, or 2.0 or more.

[0056] The high-angle antireflection laminate and the high-angle antireflection porous film of the present embodiment can be obtained by, for example, preparing the coating liquid that contains the above-mentioned binder resin and matting agent, and the optional components (light-shielding agent, various additives) that are mixed as needed in a solvent, coating this coating liquid on the surface of substrate, drying, and then carrying out heat treatment or pressure treatment etc. as needed, thereby forming the high-angle antireflection porous film on the surface of substrate.At this time, from the viewpoint of realizing the desired film density and BET specific surface area with good reproducibility, spray coating method (spray coating method) is preferably used as the coating method.That is, by applying the above-mentioned coating liquid on the surface of substrate by spray coating method (spray coating method), the fine particles of paint are made to fly and land on substrate, the high-angle antireflection laminate and the high-angle antireflection porous film of the present embodiment can also be obtained. In addition, the high-angle antireflection laminate and the high-angle antireflection porous film of this embodiment can also be obtained by, for example, preparing a coating liquid containing a binder resin and optional components (light-shielding agent, various additives) blended as needed in a solvent, and applying this coating liquid to the surface of a substrate by a spray coating method (spray coating method), thereby causing fine particles of the paint to fly and land.In this specification, the spray coating method is used as a general term for a coating method that adopts the principle of forming a film by stacking fine coating particles (i.e., a coating method that sprays fine droplets), and is a term that includes air spray method, airless spray method, micromist coating method, ultrasonic spray method, electrostatic spray method (electrostatic spray method), inkjet method, electrostatic inkjet method, etc. In the spray coating method, coating is performed repeatedly by propelling fine particles of paint onto a substrate, which makes it easy to form unevenness in the coating film that is formed and to obtain a coating film that contains voids. Therefore, this method is suitable as a method for producing the high-angle antireflection laminate and high-angle antireflection porous film of the present embodiment that have the desired film density and BET specific surface area.The dispersion medium that can be used here is not particularly limited, but examples thereof include water; ketone-based solvents such as methyl ethyl ketone, methyl isobutyl ketone, and cyclohexanone; ester-based solvents such as methyl acetate, ethyl acetate, and butyl acetate; ether-based solvents such as methyl cellosolve and ethyl cellosolve; alcohol-based solvents such as methyl alcohol, ethyl alcohol, and isopropyl alcohol; nonpolar solvents such as hexane and cyclohexane; aprotic polar solvents such as dimethylformamide; aromatic solvents such as toluene; and mixed solvents thereof, but are not particularly limited to these.

[0057] In order to improve the adhesion between the substrate and the high-angle antireflection porous film, various known surface treatments such as anchor treatment and corona treatment may be performed on the substrate surface as needed. Also, if necessary, an intermediate layer such as a primer layer or an adhesive layer may be provided on the substrate in advance, and the high-angle antireflection porous film may be formed on this intermediate layer. After forming the film in this way, the high-angle antireflection porous film may be formed as needed by ionizing radiation treatment, heat treatment, and / or pressure treatment. Furthermore, after forming it into a sheet, it may also be subjected to vacuum forming, pressure forming, etc.

[0058] The coating liquid used in spray coating contains at least a binder resin, a matting agent, and a solvent, and preferably further contains a light-shielding agent such as carbon black, and a paint containing 100 to 1,000 parts by mass of the matting agent in terms of solid content per 100 parts by mass of the solid content of the binder resin is preferably used. The types and content ratios of the binder resin, matting agent, light-shielding agent, and solvent that can be used here have already been described above, so a duplicated description will be omitted here.

[0059] (Function) In the high-angle antireflection laminate and high-angle antireflection porous film of this embodiment, the film density and BET specific surface area of ​​the high-angle antireflection porous film are adjusted within a predetermined range, so that the antireflection structure has a lower surface gloss in the high-angle region where the incident angle and reflection angle exceed 60°. Therefore, by using these high-angle antireflection laminates or high-angle antireflection porous films, an antireflection material with a low surface gloss in the high-angle region can be realized, and it can be particularly suitably used as an antireflection material for a bending optical system where the adverse effects of incident light and reflected light on the high-angle side exceeding 60° become apparent.

[0060] (Modification) In the first embodiment, a high-angle antireflection laminate having a two-layer laminate structure in which a high-angle antireflection porous film and a substrate are arranged in at least this order is exemplified, but two or more high-angle antireflection porous films may be provided. Also, the substrate may be omitted, and a laminate consisting of only two or more high-angle antireflection porous films may be provided.

[0061] The present invention can be widely and effectively used as a high-performance antireflection material in various optical devices, such as single-lens reflex cameras, compact cameras, video cameras, optical sensors such as infrared sensors, smartphones, etc. More specifically, the present invention can be effectively used as an antireflection material or light-blocking antireflection material provided in various locations of components that make up various optical devices, such as housings, outer barrels, inner barrels, camera housings, camera barrels, lenses, prisms, lens barrels, lens pedestal mounts, shutters, diaphragm members, light-shielding plates, light-shielding rings, lens units, and camera modules, and the present invention can be particularly effectively used as an antireflection material for the high-angle region of optical elements, such as lenses and prisms in bending optical systems.

Claims

1. 50-650kg / m ３ and a film density of 0.40 to 1.20 m ２ / g (based on JIS Z8830 (2013)).

2. The high-angle anti-reflection porous film according to claim 1, wherein the 85-degree specular gloss of one surface is 0.0% or more and 0.8% or less.

3. The high-angle anti-reflection porous film according to claim 1, which is a porous film in which a plurality of fine particles are aggregated and bonded together.

4. The high-angle anti-reflective porous film according to claim 3, wherein the microparticles are spray-dried microparticles.

5. The high-angle anti-reflection porous film according to claim 1, wherein the porous film contains a matting agent.

6. The high-angle anti-reflection porous film according to claim 1, wherein the porous film contains a binder resin.

7. The high-angle anti-reflection porous film according to claim 1, further comprising a light-blocking agent.

8. The high-angle anti-reflection porous film according to claim 7, wherein the light-blocking agent contains carbon black.

9. A high-angle anti-reflection laminate comprising a substrate and the high-angle anti-reflection porous film according to claim 1 provided on at least one surface of the substrate.

10. A coating material for forming a high-angle anti-reflection porous film, comprising at least a binder resin, a matting agent, and a solvent, wherein the matting agent is contained in an amount of 100 to 1,000 parts by mass in terms of solid content per 100 parts by mass of the solid content of the binder resin.

11. The coating material for forming a high-angle anti-reflection porous film according to claim 10, further comprising a light-shielding agent.

12. The coating material for forming a high-angle anti-reflection porous film according to claim 11, wherein the light-shielding agent contains carbon black.

13. The coating material for forming a high-angle anti-reflection porous film according to claim 10, which is for spray-drying coating.

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