Antireflection coating film, optical member, and antireflection coating material

Abstract

A surface reflection preventing film which does not have a problem of particles being peeled off from the film and has a small total reflectance can be provided. The surface reflection preventing film of the present invention is characterized by containing: a binder resin; carbon black; and silica, wherein the arithmetic average roughness (Ra) of the aforementioned surface reflection preventing film is 0.3 μm or more and 3.0 μm or less, and the length ratio of expansion (Rlr) is 1.6 or more, the specific surface area of the aforementioned carbon black is 175 m 2 / g or more and 400 m 2 / g or less, the content ratio of the aforementioned carbon black is 2.5 parts by mass or more and 28.0 parts by mass or less with respect to 100 parts by mass of the aforementioned binder resin, and the content ratio of the aforementioned silica is 16.0 parts by mass or more and 28.0 parts by mass or less with respect to 100 parts by mass of the aforementioned binder resin.

Description

Technical Field

[0001] The present invention relates to an anti-reflective coating, an optical component using the aforementioned anti-reflective coating, and an anti-reflective coating material for forming the aforementioned anti-reflective coating. Background Technology

[0002] In optical devices such as cameras and camcorders, stray light is generated due to diffuse reflection and scattering in the optical path of the lens barrel and other components. This can cause ghosting and flare in the image, sometimes contributing to image quality degradation. Therefore, to suppress this degradation in optical performance caused by stray light, anti-reflective coatings are applied to the optical path of the lens barrel, aperture, etc., to form an anti-reflective film, or an anti-reflective film is applied.

[0003] On the other hand, black anti-reflective coatings and films are not limited to optical devices such as cameras. They are also used in light-emitting display devices such as car dashboards and head-up displays to improve visibility by reducing peripheral reflections.

[0004] In addition, black anti-reflective coatings and anti-reflective films are also attracting attention as coatings that enhance design.

[0005] Patent document 1 proposes a coating composed of binder resin, carbon black, hydrophobically treated dry silica, and polyamide resin particles for forming an anti-reflective film.

[0006] In addition, Patent Document 2 proposes a coating composed of resin components and two types of inorganic particles: small-diameter and large-diameter particles.

[0007] Existing technical documents

[0008] Patent documents

[0009] Patent Document 1: International Publication No. 2019 / 124202

[0010] Patent Document 2: Japanese Patent Application Publication No. 2023-16200 Summary of the Invention

[0011] The problem the invention aims to solve

[0012] However, the total light reflectance (hereinafter also referred to as "total light reflectance") of the coating film formed using the anti-reflective coating described in Patent Document 1 shows an excellent value. On the other hand, since large-diameter resin particles with an average particle size of 10μm to 20μm are used, there is a problem of particle detachment due to reduced adhesion between the binder and the resin particles. In addition, Patent Document 2 discloses a coating film formed by spray coating using a coating that does not use large-diameter particles, wherein the spray coating is performed by using a coating with a particle content greater than 100 parts by mass of resin. Spray coating forms a film by drying and curing spray-based droplets, and especially when the particle content is high, there is concern about the coating surface detachment depending on the degree of adhesion of the droplets constituting the film. Furthermore, there is room for improvement in terms of total reflectance.

[0013] Therefore, the objective of this invention is to provide an anti-reflective coating with low total reflectivity, which does not cause concern about the shedding of contained particles.

[0014] Solution for solving the problem

[0015] This invention relates to an anti-reflective coating, characterized in that it contains: a binder resin, carbon black, and silicon dioxide. In the anti-reflective coating containing the aforementioned binder resin, carbon black, and silicon dioxide, the arithmetic mean roughness (Ra) of the anti-reflective coating is 0.3 μm or more and 2.0 μm or less, and the unfolded length ratio (Rlr) is 1.6 or more. The specific surface area of ​​the aforementioned carbon black is 175 m². 2 / g or more and 400m 2 / g or less, relative to 100 parts by weight of the aforementioned binder resin, the content of the aforementioned carbon black is 2.5 parts by weight or more and 28.0 parts by weight or less, and relative to 100 parts by weight of the aforementioned binder resin, the content of the aforementioned silica is 16.0 parts by weight or more and 26.0 parts by weight or less.

[0016] In addition, the present invention is an optical component having the anti-reflective film described above.

[0017] In addition, the present invention provides an anti-reflective coating, characterized in that it contains: binder resin, carbon black, and silicon dioxide, wherein the specific surface area of ​​the aforementioned carbon black is 175 m². 2 / g or more and 400m 2 The carbon black content is 2.5 parts by weight or more and 28.0 parts by weight or less, relative to 100 parts by weight of the aforementioned binder resin, and the specific surface area of ​​the aforementioned silica is 130 m² / g or less. 2 / g or more and 400m 2 The content of silica is 16.0 parts by weight or more and 28.0 parts by weight or less, relative to 100 parts by weight of the aforementioned adhesive resin.

[0018] The effects of the invention

[0019] According to the present invention, it is possible to provide an anti-reflective coating with low total reflectivity, which does not cause concern about the shedding of contained particles. Attached Figure Description

[0020] Figure 1 These are scanning electron microscope images showing the surface condition in Example 1.

[0021] Figure 2 These are scanning electron microscope images showing the surface condition in Comparative Example 1.

[0022] Figure 3 This is a diagram used to illustrate the method for measuring total light reflectance. Detailed Implementation

[0023] The following describes the methods for carrying out the present invention. Hereinafter, the anti-reflective coating film will sometimes be referred to simply as a "coating film", and the anti-reflective paint coating will sometimes be referred to simply as a "coating".

[0024] The anti-reflective coating of the present invention contains binder resin, carbon black and silicon dioxide.

[0025] The coating of the present invention is preferably in the following state: Figure 1 As shown, there are no large bumps or depressions that would cause the coating to peel off as a whole; it is smooth macroscopically, but has fine bumps or depressions microscopically. Figure 2 The surface shown is smooth on a macroscopic level, but lacks fine micro-level irregularities, resulting in a high total reflectance value, which is not preferred.

[0026] In this embodiment, the surface roughness of the anti-reflective coating needs to be an arithmetic mean roughness (Ra) of 0.3 μm or more and 2.0 μm or less, and an unfolded length ratio (Rlr) of 1.6 or more. By making Ra 0.3 μm or more and Rlr 1.6 or more, a dense coating with fine unevenness can be obtained, through which light can be absorbed and reflection suppressed. In addition, by making Ra 2.0 μm or less, particle shedding caused by unevenness can be suppressed.

[0027] Surface roughness was measured using a non-contact laser measuring instrument. Specifically, a color 3D laser microscope VK-8710 (manufactured by KEYENCE CORPORATION) was used with a 100x standard objective lens (CF IC EPI Plan 100X). Surface data were measured at a measurement interval of 0.2 μm. Roughness was calculated using the accompanying software VK-Analyzer (manufactured by KEYENCE CORPORATION). A straight line with a measurement length of 140 μm was extracted from the measured surface data, and Ra and Rlr were calculated under the conditions of no λs and no λc. It should be noted that the average value of n=3 was calculated as Ra and Rlr for each value.

[0028] It should be noted that the arithmetic mean roughness (Ra) represents the average of the absolute values ​​of the undulations over the measured length, and is a value calculated using the following formula.

[0029]

[0030] Here, Ir is the reference length and X is the measured length.

[0031] The unfolded length ratio (Rlr) is the value calculated by the following formula, which is the ratio of the length of the measured contour curve extracted from the above Ra measurement to the length of the measured curve when the curve is extended into a straight line.

[0032]

[0033] Yn=Z n+1 -Z n Here, X is the distance between measurement points (in the description of the "Evaluation" [Surface Roughness] section below, X is called the measurement interval), Zn is the value of the unevenness height at point n, and Yn is the difference between the measured unevenness height at point n+1 and the measured unevenness height at point n.

[0034] Furthermore, the anti-reflective coating of the present invention is macroscopically smooth, but microscopically has fine irregularities, thus exhibiting high water repellency. Generally speaking, a contact angle with water exceeding 90 degrees (°) is considered water repellency, exceeding 110 degrees is considered high water repellency, and exceeding 150 degrees is considered super water repellency. The contact angle of the anti-reflective coating of the present invention is preferably 95.0° or higher.

[0035] In addition, due to its low light transmittance, a coating film that does not affect the color of the substrate can be obtained. Therefore, it can be used as a stain-resistant coating film and a paint for stain-resistant coating film, whether indoors or outdoors.

[0036] The carbon black content is 2.5 parts by weight or more and 28.0 parts by weight or less relative to 100 parts by weight of binder resin. Preferably, it is 11.0 parts by weight or more and 28.0 parts by weight or less, more preferably 13.0 parts by weight or more and 25.0 parts by weight or less. If it is 2.5 parts by weight or more, it appropriately forms an uneven surface together with the silica (described later), which can suppress the total reflectance value to a low level, and also sufficiently block light. This blocking effect reduces the amount of light reaching the substrate through the coating film. Light reflected from the substrate through the coating film may affect the total reflectance and the color tone of the coating film; therefore, a low content is preferable. Furthermore, if it is 28.0 parts by weight or less, the viscosity of the coating will not increase excessively, maintaining coatability. If it is 25.0 parts by weight or less, the coatability is even better, and the total reflectance value can be suppressed even further.

[0037] In this invention, 100 parts by weight of binder resin means: when the coating or paint contains a curing agent, it represents the total amount including the binder resin and the curing agent; when the paint contains a solvent, it represents the amount of solid components after the solvent has been removed.

[0038] The carbon black used in this invention must have a nitrogen adsorption-based specific surface area of ​​175 m². 2 / g or more and 400m 2 The concentration is below / g. This is believed to be because if the specific surface area based on nitrogen adsorption is large, the primary particle size of carbon black becomes smaller, resulting in a large number of fine particles, thus increasing the probability of particles coming into contact with light. By using a specific surface area based on nitrogen adsorption of 175m², [further details are needed]. 2 Carbon black of 400 μg or higher can suppress reflection to a low level. However, if the reflection exceeds 400 μm... 2 If the specific surface area of ​​carbon black is less than 1 g, the viscosity of the coating will increase excessively, making it difficult to maintain its coatability. Here, the specific surface area of ​​carbon black can be determined using a value based on the method specified in JIS K 6217-2:2017.

[0039] Furthermore, the preferred carbon black has a low DBP oil absorption. Specifically, it is preferably below 100 ml / 100 g. DBP oil absorption indicates the development of the structure as a primary aggregate. Generally, the smaller the particle size of the carbon black, the more likely the aggregates are to develop. The carbon black used in this invention is preferably of a type with a less developed structure compared to its particle size. It is believed that the aggregated system exists as small units, thus allowing for further light absorption. Furthermore, if it is within the aforementioned range, the viscosity of the coating will not increase excessively, resulting in good coatability.

[0040] Silica is used to impart appropriate unevenness to the coating film. The content of silica must be at least 16.0 parts by weight and no more than 28.0 parts by weight relative to 100 parts by weight of the binder resin. Preferably, it is at least 19.5 parts by weight and no more than 22.5 parts by weight. If it is 16.0 parts by weight or more, sufficient convex portions can be obtained, reducing the total reflectance. Conversely, if it is 28.0 parts by weight or less, concave portions can be ensured in the coating film, resulting in a well-textured coating film.

[0041] By using a concentration of 19.5 parts by weight or more and 22.5 parts by weight or less, the viscosity of the coating will not increase excessively, thus achieving good coatability.

[0042] The preferred specific surface area of ​​silicon dioxide is 130 m². 2 / g or more and 400m 2 / g or less, more preferably 150m 2 / g or more and 400m 2 Below / g. By being within this range, it is easy to create appropriate unevenness, thus suppressing the total reflectance to a low level.

[0043] The specific surface area of ​​silica is less than 150 m². 2 / g or more than 400m 2 At a rate of / g, it is sometimes difficult to reduce the total reflectance. When using such silica, it is difficult to obtain a preferred unevenness, such as... Figure 2 As shown, sometimes the unevenness is reduced by being buried by the adhesive resin, making it impossible to suppress the total reflectance to a low level. Here, the specific surface area of ​​silica can be obtained based on the measurement method according to JIS K 6430:2008.

[0044] The preferred oil absorption capacity of silica is 270 ml / 100g or more. Silica rarely exists as primary particles alone, but mostly as secondary particles. Here, oil absorption capacity refers to the oil absorption capacity of linseed oil according to JIS K5101-13. A high oil absorption capacity results in numerous pores within the secondary silica particles, meaning a large volume, thus making it prone to unevenness. By achieving an oil absorption capacity of 270 ml / 100g or more, sufficient unevenness can be obtained when forming the coating film, thereby reducing the total reflectance.

[0045] The silica is further preferably chain-like silica with a pore volume of 1.6 ml / g or more. Chain-like silica refers to wet silica manufactured by the gelation method. The gelation method is a manufacturing method that involves a neutralization reaction of sodium silicate with an inorganic acid under acidic conditions, causing the silica to aggregate while suppressing the growth of primary particles, thus forming a three-dimensional network structure. The secondary particles of chain-like silica are firm and not easily collapsed, making it easier to maintain an uneven surface when processed into coatings or films, and is therefore more preferable.

[0046] Furthermore, a larger pore volume results in a higher volume, making it easier to form an uneven silica film. By achieving a pore volume of 1.6 ml or more, sufficient unevenness can be obtained during coating formation, thereby reducing the total reflectance.

[0047] Furthermore, anti-reflective coatings sometimes need to withstand light incident from various angles, depending on the application. In cases where it is necessary to minimize reflection of light from the sides of the coating, greater unevenness is required. Therefore, it is preferable to contain large particles. The silica used in this invention can be combined with silicas having different average particle sizes, preferably containing silica with an average particle size of 8.0 μm or more and 15.0 μm or less, more preferably in combination with silica with an average particle size of 2.0 μm or more and less than 8.0 μm.

[0048] It should be noted that silica has a large surface area and excellent adhesion to adhesive resins, making it less likely to detach due to increased particle size, as is the case with resin particles.

[0049] By making the average particle size of silica (B) 8.0 μm or more, the reflection of light from the lateral direction can be suppressed to a low level, and by setting it to 15.0 μm or less, particle shedding can be suppressed.

[0050] Here, the average particle size of silica can be obtained using a value based on the laser analysis / scattering method according to JIS Z8825:2013.

[0051] When silica with an average particle size of 8.0 μm or more and 15.0 μm or less is defined as silica (B), the content of silica (B) relative to the total mass of silica used in this invention is preferably 5% by mass or more and 30% by mass or less, more preferably 10% by mass or more and 20% by mass or less.

[0052] By setting the silica (B) content to 5% by mass or more, the effect on gloss is further enhanced; by setting it to 30% by mass or less, a balance can be achieved with the total reflection while improving the gloss effect.

[0053] Reflection from transverse incident light can be evaluated by measuring specular gloss. Hereinafter, specular gloss will sometimes be referred to simply as gloss. The lower the specular gloss, the less reflection, which is preferable. Specular gloss can be measured using the method described in JIS Z8741:1997. Specifically, the gloss of the coating surface is measured using a portable gloss meter PG-IIM manufactured by Nippon Denshoku Kogyo Co., Ltd. Specifically, the gloss at 60° of "Method 3" as described in JIS is measured, and if the gloss is 10 or less, the gloss at 85° of "Method 1" as applicable to "Method 3" with a gloss of 10 or less is measured and evaluated.

[0054] In this embodiment, the adhesive resin is not particularly limited. For example, acrylic resins, polyurethane resins, epoxy resins, alkyd resins, polyester resins, and other resins can be used. These adhesive resins can be used alone or in combination of two or more. Among these, considering lightfastness and adhesion to the substrate, a two-component reactive acrylic resin is more preferred.

[0055] Examples of two-component reactive acrylic resins include copolymers of comonomers such as acrylic acid, acrylates, methacrylic acid, styrene, acrylamide, vinyltoluene, glycidyl methacrylate, and hydroxyethyl acrylate. Acrylic polyols, which are copolymers of acrylates and vinyl compounds, are widely used because their properties are easy to adjust.

[0056] When using two-component reactive acrylic resins, various curing agents can be used. For example, for acrylic polyols, examples include aliphatic diisocyanates such as hexamethylene diisocyanate (HMDI) and trimethylhexamethylene diisocyanate (TMDI); alicyclic diisocyanates such as isophorone diisocyanate (IPDI); aromatic-aliphatic diisocyanates such as phenyl diisocyanate (XDI); aromatic diisocyanates such as toluene diisocyanate (TDI) and 4,4-diphenylmethane diisocyanate (MDI); and isocyanate compounds such as dimer diisocyanate (DDI), hydrogenated TDI (HTDI), hydrogenated XDI (H6XDI), and hydrogenated MDI (H12MDI).

[0057] In this embodiment, the coating material that forms the film preferably also contains a solvent. From the viewpoint of the solubility of the binder resin, an organic solvent is preferred. The coating material may be prepared by dispersing and diluting the aforementioned binder resin, carbon black, silica, etc., with the aforementioned organic solvent.

[0058] Solvents can be commonly known solvents used in coatings. Specific examples of solvents include the following.

[0059] Chain hydrocarbons such as neopentane, n-hexane, n-heptane, and solvesse; aromatic hydrocarbons such as toluene and xylene; halogenated hydrocarbons such as trichloroethylene and perchloroethylene; alcohols such as methanol, ethanol, isopropanol, and n-butanol; ketones such as acetone, methyl ethyl ketone, and methyl isobutyl ketone; esters such as ethyl acetate and n-butyl acetate; ethers such as cellosol, butyl cellosol, and acetic acid cellosol; and mineral oils (hydrocarbon oils).

[0060] It should be noted that the solvents mentioned above can be used alone, or in any combination of two or more in any ratio. For example, by mixing multiple solvents, the drying rate can be controlled.

[0061] The dilution rate can also be adjusted arbitrarily according to the application. For example, it can be appropriately adjusted according to the application method such as an applicator, brush, sprayer, etc. By using the coating of the present invention, even by the conventionally known application methods such as applicators, brushes, rollers, roller coating, spraying, and dip coating, an anti-reflective coating film with low total reflectivity that can be formed without worrying about the shedding of contained particles can be provided.

[0062] In this embodiment, other additives may be included while maintaining the anti-reflective properties of the formed coating.

[0063] For example, additives such as pigments, resin particles, dispersants, leveling agents, thickeners, preservatives, and mildew inhibitors can be used, and one or more of them can be used.

[0064] To adjust the viscosity of the coating, thickeners such as bentonite, silicone elastomers, thickening polysaccharides, and glycols, as well as diluents, can be used.

[0065] In order to improve the adhesion of the obtained coating to the substrate, in addition to the silane coupling agents mentioned above, organosilicon coupling agents, aluminate coupling agents, titanate coupling agents, etc. can also be used.

[0066] To improve the leveling properties of the resulting coating, leveling agents such as silicone oil and surfactants can be used.

[0067] To improve the matting properties of the obtained coating surface, resin particles, glass powder, quartz powder, mica powder, etc. can be used.

[0068] To adjust the tone of black, dyes, organic pigments, and inorganic pigments that are complementary colors can also be used.

[0069] To improve the lightfastness of the resulting coating, various UV absorbers can be used, including benzophenone-based, salicylate-based, triazine-based, benzotriazole-based, zinc oxide microparticles, and titanium oxide microparticles.

[0070] Examples of preservatives and fungicides include benzimidazole series, isothiazole series, haloallyl sulfone series, iodopropynyl series, benzothiazole series, phenol series, triazine series, adamantane series, pyridine series, etc.

[0071] The total reflectance of the present invention is also called the total light reflectance. If the total reflectance of 400nm to 700nm is less than 3.0%, it can be used as an anti-reflective coating, preferably less than 2.4%, and more preferably less than 2.2%.

[0072] Total reflectance was measured using a spectrophotometer equipped with an integrating sphere (e.g., trade name: V-670, manufactured by Nippon Spectrophotometer Co., Ltd.).

[0073] <Manufacturing Method of Anti-reflective Coating>

[0074] Anti-reflective coatings can be manufactured by mixing and dispersing binder resins, carbon black or dyes, resin particles, silica, and other materials such as solvents as needed. The dispersion of the mixed solution can be carried out using known dispersion methods, such as ball mills, paint mixers, basket mills, DYNO-MILL, Ultra Visco Mill, and ring dispersers.

[0075] <Manufacturing Method of Anti-reflective Coating>

[0076] The anti-reflective coating of the present invention can be applied to a substrate, dried, and cured to form an anti-reflective coating film. It can be applied to known substrates such as glass, resin, and metal. The method for forming the coating film is not particularly limited, and known coating methods can be used. Examples of coating methods include applicators, brushes, rollers, roller coating, spraying, and dip coating. Furthermore, the drying and curing methods can be selected according to the application, such as hot air, far-infrared radiation, or natural drying.

[0077] Example

[0078] The present invention will now be described in more detail by way of examples and comparative examples, but the present invention is not limited to these examples.

[0079] The following shows the raw materials used in the various embodiments and comparative examples.

[0080] [Adhesive Resin]

[0081] Coatax LH-601 (manufactured by TORAY FINE CHEMICALS CO., LTD.) is a two-component cured acrylic polyol.

[0082] • ACRYDIC A-817 (manufactured by DIC Corporation) Two-component cured acrylic polyol

[0083] ·DURANOL G4672 (manufactured by Asahi Kasei Corporation) Two-component cured polyol

[0084] EP4100 (manufactured by ADEKA Co., Ltd.) is a two-component curable epoxy resin.

[0085] [Curing agent]

[0086] • BURNOCK DN981 (manufactured by DIC Corporation) isocyanurate type curing agent

[0087] ·jER Cure 113 (manufactured by Mitsubishi Chemical Corporation) Alicyclic amine curing agent

[0088] Silicon dioxide

[0089] Nipgle AZ204 (manufactured by Tosoh Silica Corporation) has a BET specific surface area of ​​300 m². 2 / g, oil absorption 355ml / 100g, average particle size 2.9μm, gel-processed silica (pore volume 2.0ml / g)

[0090] Nipgle AZ200 (manufactured by Tosoh Silica Corporation) has a BET specific surface area of ​​300 m². 2 / g, oil absorption 330ml / 100g, average particle size 4.2μm, gel-processed silica (pore volume 2.0ml / g)

[0091] Nipgle AZ400 (manufactured by Tosoh Silica Corporation) has a BET specific surface area of ​​300 m². 2 / g, oil absorption 315ml / 100g, average particle size 7.1μm, gel-processed silica (pore volume 2.0ml / g)

[0092] Nipgle AY200 (manufactured by Tosoh Silica Corporation) has a BET specific surface area of ​​300 m². 2 / g, oil absorption 280ml / 100g, average particle size 3.6μm, gel-processed silica (pore volume 1.6ml / g)

[0093] Nipsil E220A (manufactured by Tosoh Silica Corporation) has a BET specific surface area of ​​150 m². 2 / g, oil absorption 350ml / 100g, average particle size 4.2μm, sedimentation silica

[0094] Nipsil SP200 (manufactured by Tosoh Silica Corporation) has a BET specific surface area of ​​198 m². 2 / g, sedimentation method for silica

[0095] • ACEMATT OK412 (manufactured by EVONIC) BET specific surface area 130m² 2 / g, average particle size 6.3μm, sedimentation silica

[0096] Nipgle AZ6A0 (manufactured by Tosoh Silica Corporation) has a BET specific surface area of ​​300 m². 2 / g, oil absorption 315ml / 100g, average particle size 9.3μm, gel-processed silica (pore volume 1.3ml / g)

[0097] Nipgle AY8A2 (manufactured by Tosoh Silica Corporation) has a BET specific surface area of ​​350 m². 2 / g, oil absorption 250ml / 100g, average particle size 13.4μm, gel-processed silica (pore volume 1.4ml / g)

[0098] • Nipgle BY001 (manufactured by Tosoh Silica Corporation) BET specific surface area 450m² 2 / g, oil absorption 200ml / 100g, average particle size 14.3μm, gel-processed silica (pore volume 1.3ml / g)

[0099] Nipgle BZ400 (manufactured by Tosoh Silica Corporation) has a BET specific surface area of ​​450 m². 2 / g, oil absorption 315ml / 100g, average particle size 6.0μm, gel-processed silica (pore volume 1.8ml / g)

[0100] Nipgle CX200 (manufactured by Tosoh Silica Corporation) has a BET specific surface area of ​​750 m². 2 / g, oil absorption 115ml / 100g, average particle size 2.2μm, gel-processed silica (pore volume 0.5ml / g)

[0101] • Nipgle BY200 (manufactured by Tosoh Silica Corporation) BET specific surface area 450m² 2 / g, oil absorption 220ml / 100g, average particle size 2.6μm, gel-processed silica (pore volume 1.3ml / g)

[0102] [Carbon black]

[0103] • RAVEN 5000UII (manufactured by Columbia Chemical Corporation) has a nitrogen specific surface area of ​​350 m². 2 / g, DBP oil absorption 95cm 3 / 100g

[0104] Mitsubishi Carbon Black #2650 (manufactured by Mitsubishi Chemical Corporation) has a nitrogen specific surface area of ​​370 m². 2 / g, DBP oil absorption 73cm 3 / 100g

[0105] Mitsubishi Carbon Black #1000 (manufactured by Mitsubishi Chemical Corporation) has a nitrogen specific surface area of ​​180 m². 2 / g, DBP oil absorption 56cm 3 / 100g

[0106] TOKABLACK#5500 (manufactured by Tokai Carbon Co., Ltd.) has a nitrogen specific surface area of ​​225 m². 2 / g, DBP oil absorption 155cm 3 / 100g

[0107] • SUNBLACK235 (manufactured by ASAHI CARBON CO.,LTD.) has a nitrogen specific surface area of ​​24 m². 2 / g, DBP oil absorption 49cm 3 / 100g

[0108] [dye]

[0109] ·OIL BLACK HBB (made by ORIENT CHEMICAL INDUSTRIES CO.,LTD)

[0110] ·VALIFAST BLACK 3820 (manufactured by ORIENT CHEMICAL INDUSTRIES CO.,LTD)

[0111] [Resin particles]

[0112] • DAIAMID WS200P (manufactured by Daicel-Evonik) polyamide (PA) resin particles (average particle size 80μm)

[0113] • VESTOSINT 2157 (manufactured by Daicel-Evonik) polyamide (PA) resin particles (average particle size 50 μm)

[0114] <Preparation of Anti-reflective Coatings>

[0115] The materials were mixed according to the ratios shown in Table 1 or Table 2 to obtain the anti-reflective coatings of Examples 1-24 and Comparative Examples 1-10. The values ​​of each material listed in Table 1 or Table 2 are parts by weight relative to the total solid content of the binder resin and the curing agent. In addition, the values ​​in parentheses for the binder and curing agent in the tables are the solid content.

[0116] Weigh all materials except the hardener, disperse them using a paint mixer, and then stir the hardener using a manual mixer to obtain the anti-reflective coating. Details will be described later in Example 1.

[0117] <Production of Anti-reflective Film>

[0118] The anti-reflective coating obtained by the above method is applied using an applicator to obtain an anti-reflective film. Details are described later in Example 1.

[0119] <Evaluation>

[0120] The anti-reflective films produced in each embodiment and comparative example are evaluated as follows.

[0121] Surface roughness

[0122] Surface roughness was measured using a non-contact laser measuring instrument. Specifically, a color 3D laser microscope VK-8710 (manufactured by KEYENCE CORPORATIO) was used with a 100x standard objective lens (CF IC EPI Plan 100X) at a measurement interval of 0.2 μm to measure surface data. Roughness was calculated using the accompanying software VK-A nalyzer (manufactured by KEYENCE CORPORATIO). A straight line with a measurement length of 140 μm was extracted from the measured surface data, and Ra and Rlr were calculated under the conditions of no λs and no λc. It should be noted that the average value of n=3 was calculated as Ra and Rlr for each value.

[0123] [film thickness]

[0124] Film thickness was measured using a micrometer. Specifically, the thickness of the coated and cured PET film at three locations was measured using a Coolant proof micrometer MDC-25MX manufactured by Mitutoyo Corporation, and the average value was calculated. The difference between the calculated value and the thickness of the uncoated PET film was taken as the film thickness.

[0125] [Total Light Reflectance Measurement]

[0126] As an evaluation of the anti-reflective coating in the visible light (400-700nm) region, the total light reflectance was measured. The total light reflectance was measured using a spectrophotometer (trade name: V-670, manufactured by Nippon Spectrophotometer Co., Ltd.) equipped with a 150mmφ integrating sphere unit on the anti-reflective coatings obtained in the above examples and comparative examples.

[0127] In the measurement, such as Figure 3 As shown, for the anti-reflective coating 1, the incident angle 7 is fixed at 7° relative to the vertically extending normal 6, and incident light 2 is incident in 1 nm increments within the wavelength range of 350 nm to 850 nm. Then, the diffuse reflected light 5, including reflected light 3, is measured. Three measurements are performed on the same sample, and the average of the three measurements obtained within the wavelength range of 400 nm to 700 nm is calculated as the total reflectance to visible light. The total reflectance is evaluated as follows.

[0128] AA: The total reflectance of visible light is "less than 2.2%".

[0129] A: The total reflectance of visible light is "more than 2.2% and less than 2.4%".

[0130] B: The total reflectance of visible light is "more than 2.4% and less than 3.0%".

[0131] C: Total reflectance of visible light "exceeds 3.0%".

[0132] [Specular Gloss Measurement]

[0133] The gloss of the anti-reflective coating was evaluated according to the method described in JIS Z8741:1997. For the anti-reflective coatings obtained in the above examples and comparative examples, the gloss of the coating surface was measured using a portable gloss meter PG-IIM manufactured by Nippon Denshoku Kogyo Co., Ltd. The gloss at 60° as described in JIS "Method 3" was measured, and the result was 10 or less. Therefore, the gloss at 85° as described in "Method 3" (gloss of 10 or less) is applicable to "Method 1". Based on the measured gloss, the following evaluation was conducted.

[0134] AA: The gloss level of 85° is "below 1.5".

[0135] A: 85° gloss is “above 1.5 and below 3.0”.

[0136] B: 85° gloss level "over 3.0".

[0137] [Tape peeling]

[0138] The evaluation of tape peeling of the anti-reflective coating was conducted as follows. For the anti-reflective coatings obtained in the above examples and comparative examples, Cellottape (registered trademark) No. 405 (manufactured by NICHIBAN Co., Ltd.) was placed and rubbed back and forth 15 times each in a 18mm x 18mm area with an eraser. Then, Cellottape (registered trademark) No. 405 (manufactured by NICHIBAN Co., Ltd.) was peeled off from the anti-reflective coating to visually inspect for black spots caused by particles detaching from the coating. The evaluation was conducted according to the following criteria.

[0139] A: The number of black dots is 0.

[0140] B: There is more than 1 black dot and less than 5 black dots.

[0141] C: There are 5 or more black dots.

[0142] [Comprehensive Judgment]

[0143] 〇: Total reflection is judged as AA~B, tape peeling is judged as A~B, and no C is judged for any of the following.

[0144] ×: C is present in either the determination of total reflection or the determination of tape peeling.

[0145] [Transmittance Measurement]

[0146] Transmittance was measured to evaluate the anti-reflective coating in the visible light (400~700nm) region. For the anti-reflective coatings obtained in the above examples and comparative examples, transmittance was measured using a spectrophotometer (trade name: V-670, manufactured by Nippon Spectrophotometer Co., Ltd.) equipped with a 150mmφ integrating sphere unit.

[0147] During the measurement, an anti-reflective coating was installed near the entrance window of the integrating sphere unit, such as... Figure 3 As shown, for the anti-reflective coating 1, the incident angle 7 is fixed at 0° relative to the vertically extending normal 6, and incident light 2 is incident in 1 nm increments within the wavelength range of 350 nm to 850 nm. Then, the transmitted light 4 is measured. Three measurements are performed on the same sample, and the average of the three measurements obtained within the wavelength range of 400 nm to 700 nm is calculated as the transmittance to visible light.

[0148] [Contact Angle]

[0149] To evaluate the contact angle of the anti-reflective coating, the following measurements were performed. For the contact angle measurements, a droplet method contact angle measuring device (trade name: DropMaster DM500, manufactured by Kyowa Interface Science Co., Ltd.) was used for the anti-reflective coatings obtained in the above examples and comparative examples. A droplet of 1.0 μl of ion-exchanged water was prepared using a syringe, and the angle between the coating and the droplet when the droplet landed on the coating surface was measured. The average of the three measured values ​​was calculated as the contact angle.

[0150] (Example 1)

[0151] <Preparation of Anti-reflective Coatings>

[0152] Weigh each material in a 100ml glass bottle, totaling 50g, according to the following ratio. Add 22.3 parts by weight of carbon black (RAVEN 5000UII), 22.3 parts by weight of silica (Nipgel AZ204), and 156.7 parts by weight of diluent to 180 parts by weight of adhesive resin (Coatax LH-601) (90 parts by weight of solids) to obtain a coating mixture. Add diluent so that the total solvent in the adhesive resin solution and the subsequently added curing agent solution reaches 250 parts by weight. Further add 50g of dispersing glass beads (1.5mm particle size) to the above coating mixture and disperse using a paint stirrer for 10 minutes. Then, filter through a nylon mesh (250μm pore size). Take 10g from the filtered sample, add 13.3 parts by weight of curing agent (BURNOCK DN981) (10 parts by weight of solid component), and stir with a manual mixer for 2 minutes to obtain the anti-reflective coating of Example 1.

[0153] <Production of Anti-reflective Film>

[0154] Using a 150 μm applicator, the anti-reflective coating obtained by the above method was applied to a polyethylene terephthalate (PET) film. After air drying for 5 minutes, it was cured at 100°C for 2 hours to obtain the anti-reflective film. The thickness of the cured coating was 28 μm.

[0155] (Examples 2-4, 44, 45)

[0156] As shown in Table 1 or Table 3, the binder resin, curing agent, and solvent of Example 1 were modified, and the dilution dosage was adjusted accordingly. Otherwise, the coating was prepared in the same manner as in Example 1. Furthermore, the resulting coating was used to prepare a film in the same manner as in Example 1. The evaluation results are shown in Table 1 or Table 2.

[0157] (Examples 5-13, Comparative Examples 7-10)

[0158] The proportions of carbon and silica in Example 1 were modified as shown in Table 1 or Table 3, but the coating was prepared in the same manner as in Example 1. Furthermore, the resulting coating was used to create a film in the same manner as in Example 1. The evaluation results are shown in Table 1 or Table 3.

[0159] (Examples 14-16, Comparative Example 6)

[0160] As shown in Table 1 or Table 3, the type of carbon in Example 1 was changed, but the coating was prepared in the same manner as in Example 1. Furthermore, the resulting coating was used to create a film in the same manner as in Example 1. The evaluation results are shown in Table 1 or Table 3.

[0161] (Examples 17-23, 26-34, Comparative Examples 1 and 2)

[0162] The type of silica in Example 1 was changed as shown in Tables 1, 2, or 3, but the coating was prepared in the same manner as in Example 1. Furthermore, a coating film was made using the obtained coating in the same manner as in Example 1. The evaluation results are shown in Tables 1, 2, or 3.

[0163] (Example 24)

[0164] Using the coating from Example 1, a brush was used to apply it onto a PET film. After air drying for 5 minutes, it was cured at 100°C for 2 hours to obtain an anti-reflective film. The evaluation results are shown in Table 2.

[0165] (Example 25)

[0166] Based on the coating of Example 1, butyl acetate was further added to adjust the viscosity of the coating to be suitable for spraying. Using the obtained coating, four coats were applied to a PET film using a manual spray gun RG-3L-3 manufactured by ANEST IWATA Corporation. After air drying for 10 minutes, the film was cured at 100°C for 2 hours to obtain an anti-reflective film. The evaluation results are shown in Table 2.

[0167] (Examples 35-40)

[0168] As shown in Table 2 or Table 3, the type and amount of silica in Example 1 were changed, but the coating was prepared in the same manner as in Example 1. Furthermore, the resulting coating was used to create a film in the same manner as in Example 1. The evaluation results are shown in Table 2 or Table 3.

[0169] (Examples 41-43)

[0170] Based on the coatings of Examples 32, 27, and 31, butyl acetate was further added to adjust the viscosity to a suitable level for spraying. The resulting coatings were then used to prepare coating films in the same manner as in Example 25. The evaluation results are shown in Table 3.

[0171] (Compare Examples 3 and 4)

[0172] As shown in Table 2, the dye was mixed to replace the carbon in Example 1, and the coating was prepared in the same manner as in Example 1. Furthermore, the resulting coating was used to prepare a film in the same manner as in Example 1. The evaluation results are shown in Table 3.

[0173] (Comparative Example 5)

[0174] The materials from Example 1 and further coarse particles were added: 25 parts by weight of VESTOSINT 2157 and 25 parts by weight of DAIAMID WS200P. A coating was prepared in the same manner as in Example 1. Furthermore, a coating film was made using the resulting coating in the same manner as in Example 1. The evaluation results are shown in Table 3.

[0175] [Table 1]

[0176]

[0177] [Table 2]

[0178]

[0179] [Table 3]

[0180]

[0181] This invention is not limited to the embodiments described above, and various changes and modifications can be made without departing from the concept and scope of this invention. Therefore, the above claims are appended to disclose the scope of this invention.

[0182] This application claims priority based on Japanese Patent Application No. 2023-192357, filed on November 10, 2023, the entire contents of which are incorporated herein by reference.

[0183] Explanation of reference numerals in the attached figures

[0184] 1 Anti-reflective coating

[0185] 2. Incident light

[0186] 3. Reflected light

[0187] 4. Transmitted light

[0188] 5. Diffuse light

[0189] 6. Normals

[0190] 7 Angle of incidence

Claims

1. An anti-reflective coating comprising: a binder resin, carbon black, and silicon dioxide. The anti-reflective coating has an arithmetic mean roughness Ra of 0.3 μm or more and 3.0 μm or less, and an unfolded length ratio Rlr of 1.6 or more. The specific surface area of ​​the carbon black is 175 m². 2 / g or more and 400m 2 / g or less The carbon black content is 2.5 parts by weight or more and 28.0 parts by weight or less per 100 parts by weight of the binder resin. The content of silica is 16.0 parts by mass or more and 28.0 parts by mass or less, relative to 100 parts by mass of the adhesive resin.

2. The anti-reflective coating according to claim 1, wherein, The specific surface area of ​​the silicon dioxide is 150 m². 2 / g or more and 400m 2 / g or less.

3. The anti-reflective coating according to claim 1 or 2, wherein, The silica has an oil absorption capacity of over 270ml / 100g.

4. The anti-reflective coating according to any one of claims 1 to 3, wherein, The silica is chain silica, and the pore volume of the silica is 1.6 ml / g or more.

5. The anti-reflective coating according to any one of claims 1 to 4, wherein, The silica contains silica B with an average particle size of 8 μm or more and 15 μm or less. The content of silicon dioxide B relative to the total mass of the silicon dioxide is more than 5% by mass and less than 30% by mass.

6. The anti-reflective coating according to any one of claims 1 to 5, wherein, The total reflectivity of the anti-reflective coating in the 400nm~700nm range is below 2.4%.

7. An optical component having an anti-reflective coating as described in any one of claims 1 to 6.

8. An anti-reflective coating comprising: a binder resin, carbon black, and silica. The specific surface area of ​​the carbon black is 175 m². 2 / g or more and 400m 2 / g or less The carbon black content is 2.5 parts by weight or more and 28.0 parts by weight or less per 100 parts by weight of the binder resin. The specific surface area of ​​the silicon dioxide is 130 m². 2 / g or more and 400m 2 / g or less The content of silica is 16.0 parts by mass or more and 28.0 parts by mass or less, relative to 100 parts by mass of the adhesive resin.

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