Ink for forming coated film for optical member, and optical member

Abstract

To provide an ink for forming a coated film for an optical member capable of forming a coated film for an optical member excellent in light shading property, internal reflection suppression property, refractive index, and film quality, and an application of the same.SOLUTION: An ink for forming a coated film for an optical member includes: a black pigment, at least one of a colored pigment and a colorless pigment, a binder, and a volatile constituent, where when a coated film for an optical member is formed, the average refractive index in a wavelength region of 400 nm-700 nm of the coated film for the optical member is 1.70 or higher, the average extinction coefficient k in a wavelength region of 400 nm-700 nm of the coated film for the optical member is 0.10-0.15, and the ratio of a total of the black pigment, the colored pigment, and the colorless pigment occupied in a total volume of the coated film for the optical member is 10 vol.%-40 vol.%. Also provided is an application of the same.SELECTED DRAWING: None

Description

[Technical field]

[0001] The present disclosure relates to an ink for forming a coating film for an optical member and an optical member. [Background technology]

[0002] 2. Description of the Related Art Conventionally, in order to suppress internal reflection of optical components such as lenses, paint has been applied to a part of the optical component to form a coating film (for example, this is sometimes called "inking").

[0003] For example, Patent Document 1 discloses a coating material for preventing internal reflection of optical components, which has a refractive index higher than that of optical components such as lenses and prisms and contains a metal oxide with high blackness as a main pigment.

[0004] Furthermore, Patent Document 2 discloses the following anti-internal reflection black paint for optical elements, which has a sufficient anti-internal reflection effect even for optical elements with a high refractive index and ensures coating workability even when the paint is stored for a long period of time. The black coating material for preventing internal reflection of optical elements disclosed in Patent Document 2 is as follows: A black coating material for preventing internal reflection of an optical element, comprising at least titanium dioxide, carbon black, a binder resin, a dispersant, and a solvent, The titanium dioxide has a methanol hydrophobicity of 30% or more and 80% or less, a pH of 3.0 or more and 8.0 or less, and is contained in an amount of 35% by mass or more and 75% by mass or less based on the solid content of the black coating material for anti-reflection in internal surfaces for optical elements, The carbon black has a volatile content of 0.6% by mass or more and 6.0% by mass or less, a pH of 3.0 or more and 8.0 or less, and is contained in an amount of 2% by mass or more and 20% by mass or less based on the solid content of the black coating material for anti-reflection in internal surfaces for optical elements, The dispersant is a combination of a phthalocyanine compound and a polymer dispersant, the phthalocyanine compound is contained in an amount of 1% by mass or more and 20% by mass or less relative to 100% by mass of the carbon black, The polymer dispersant has an amine value of 5 mgKOH / g or more and 100 mgKOH / g or less, and is contained in an amount of 5 mass % or more and 40 mass % or less when the total of the titanium dioxide and the carbon black is taken as 100 mass %. This is an anti-reflection black coating material for internal surfaces of optical elements. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Publication No. 57-8264 [Patent Document 2] JP 2012-149197 A Summary of the Invention [Problem to be solved by the invention]

[0006] In recent years, there has been an accelerating trend toward miniaturization and / or weight reduction of optical component products incorporating optical components (eg, lenses, prisms, waveguides, etc.). One of the methods for reducing the size and / or weight of optical component products is to use high refractive index optical components (e.g., optical components with a refractive index of 1.60 or more). High refractive index optical components can greatly bend the path of light even with a small curvature. As a result, it is possible to make the optical components thinner and reduce the number of optical components contained in the entire optical component product.

[0007] However, as the refractive index of the optical member increases and the angle at which the light path is bent increases, the amount of deviation of the light focusing position relative to the amount of deviation of the assembly position of the optical member increases, which tends to result in a deterioration in image quality. In this regard, the outer peripheral surface of the optical member serves as a positioning reference for the optical member when the optical member is incorporated into the lens frame, and therefore, any variation in the thickness of the coating film for optical members provided on the outer peripheral surface of the optical member affects the positioning accuracy of the optical member when the optical member is incorporated into the lens frame. In order to suppress the variation in the thickness of the coating film for optical components, it is effective to reduce the thickness of the coating film for optical components by increasing the light-shielding property of the coating film for optical components, thereby reducing the effect of the variation in the thickness of the coating film for optical components on the positional accuracy of the optical components. As described above, from the viewpoint of improving the positional accuracy of an optical member when the optical member is incorporated into a lens case, it is sometimes desired to improve the light-shielding properties of a coating film for optical members that is provided on the optical member.

[0008] On the other hand, there are cases where it is desired to further improve the performance of suppressing internal reflection within an optical component (hereinafter also referred to as internal reflection suppression property) and the film quality (e.g., adhesion, solvent resistance, etc.) of a coating film for an optical component.

[0009] In addition, from the viewpoint of the internal reflection suppression property of the coating film for optical components, it is desirable, based on optical principles, to make the refractive index of the substrate for optical components (e.g., a lens) and the refractive index of the coating film for optical components provided on a part of the substrate for optical components as close as possible to each other (ideally the same value). For this reason, when increasing the refractive index of the substrate for optical members, it is desirable to increase the refractive index of the coating film for optical members.

[0010] The present disclosure has been made in consideration of the above circumstances. An object of one embodiment of the present disclosure is to provide an ink for forming a coating film for optical components, which is capable of forming a coating film for optical components having excellent light blocking properties, internal reflection suppression properties, refractive index, and film quality, and an optical component provided with the above-mentioned coating film for optical components. [Means for solving the problem]

[0011] The present disclosure includes the following aspects. <1> The ink contains a black pigment, at least one of a colored pigment and a colorless pigment, a binder, and a volatile component, When the coating film is used as a coating film for optical components, the coating film for optical components has an average refractive index n of 1.60 or more in a wavelength range of 400 nm to 700 nm, an average extinction coefficient k of 0.10 to 0.15 in a wavelength range of 400 nm to 700 nm, and a total volume ratio of the black pigment, the colored pigment, and the colorless pigment to the total volume of the coating film for optical components is 10 volume % to 40 volume %. Ink for forming coatings on optical components. <2> The average refractive index n of the coating film for optical members in the wavelength region of 400 nm to 700 nm is 1.70 to 1.85. <1> The ink for forming a coating film for optical members according to claim 1. <3> The black pigment, the colored pigment, and the colorless pigment each have an average refractive index n of 2.00 or more in a wavelength region of 400 nm to 700 nm, The black pigment and the colored pigment each have an average extinction coefficient k of 0.10 or more. <1> or <2> The ink for forming a coating film for optical members according to claim 1. <4> The ink contains a black pigment, at least one of a colored pigment and a colorless pigment, a binder, and a volatile component, The black pigment, the colored pigment, and the colorless pigment each have an average refractive index n of 2.00 or more in a wavelength region of 400 nm to 700 nm, The black pigment and the colored pigment each have an average extinction coefficient k of 0.10 or more; The total mass ratio of the black pigment, the colored pigment, and the colorless pigment to the total solid content is 6.5% by mass to 25.8% by mass. Ink for forming coatings on optical components. <5> The black pigment comprises at least one selected from the group consisting of carbon black and titanium carbide; The color pigment comprises at least one selected from the group consisting of iron(III) oxide, silicon carbide, and copper(I) oxide; The colorless pigment contains at least one selected from the group consisting of titanium oxide, diamond, zirconia, and indium tin oxide; <1> ~ <4> 10. An ink for forming a coating film for optical members according to any one of the above items. <6> The median diameter of the pigment is 100 nm or less. <1> ~ <5> 10. An ink for forming a coating film for optical members according to any one of the above items. <7> The binder contains an epoxy resin having an average refractive index n of 1.60 or more in the wavelength region of 400 nm to 700 nm. <1> ~ <6> 10. An ink for forming a coating film for optical members according to any one of the above items. <8> The epoxy resin comprises a fluorene-based epoxy resin. <7> The ink for forming a coating film for optical members according to claim 1. <9> The epoxy resin includes a thermosetting epoxy resin. <7> or <8> The ink for forming a coating film for optical members according to claim 1. <10> Further, the composition contains a thiol-based curing agent as an epoxy resin curing agent and a tertiary amine as a curing accelerator. <9> The ink for forming a coating film for optical members according to claim 1. <11> The content of volatile components is 50% by mass or more based on the total amount of the ink for optical components. <1> ~ <10> 10. An ink for forming a coating film for optical members according to any one of the above items. <12> The volatile components include organic solvents with a boiling point of 180°C or less. <1> ~ <11> 10. An ink for forming a coating film for optical members according to any one of the above items. <13> The volatile component includes at least one selected from the group consisting of propyl acetate, propylene glycol monomethyl ether acetate, propylene glycol monomethyl ether, toluene, cyclohexane, and ethylene glycol monobutyl ether; <1> ~ <12> 10. An ink for forming a coating film for optical members according to any one of the above items. <14> Further, the composition contains a silane coupling agent. <1> ~ <13> 10. An ink for forming a coating film for optical members according to any one of the above items. <15> Further, the composition contains a filler. <1> ~ <14> 10. An ink for forming a coating film for optical members according to any one of the above items. <16> A substrate for optical members, A coating film for optical members provided on a part of a substrate for optical members; Equipped with A coating film for an optical member contains a black pigment and at least one of a colored pigment and a colorless pigment, has an average refractive index n of 1.70 or more in a wavelength region of 400 nm to 700 nm, has an average extinction coefficient k of 0.10 to 0.15 in a wavelength region of 400 nm to 700 nm, and the total ratio of the black pigment, the colored pigment, and the colorless pigment to the total volume is 10 volume % to 40 volume %. Optical components. <17> Optical components for broadcasting, optical components for cinema, optical components for digital cameras, optical components for industrial cameras, optical components for projectors, optical components for car-mounted cameras, optical components for smartphone-mounted cameras, optical components using prisms, or optical components using optical waveguides. <16> The optical member according to claim 1. Effect of the Invention

[0012] According to one embodiment of the present disclosure, there is provided an ink for forming a coating film for an optical component, which is capable of forming a coating film for an optical component having excellent light blocking properties, internal reflection suppression properties, refractive index, and film quality, and an optical component including the coating film for an optical component. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0013] In this specification, a numerical range indicated using "to" means a range that includes the numerical values ​​before and after "to" as the minimum and maximum values, respectively. In the numerical ranges described in this specification, the upper or lower limit value described in a certain numerical range may be replaced with the upper or lower limit value of another numerical range described in a certain numerical range. In addition, in the numerical ranges described in this specification, the upper or lower limit value described in a certain numerical range may be replaced with a value shown in the examples.

[0014] In this specification, the amount of each component in a composition means the total amount of the multiple substances present in the composition when multiple substances corresponding to each component are present in the composition, unless otherwise specified. As used herein, a combination of two or more preferred embodiments is a more preferred embodiment. In this specification, the term "process" includes not only an independent process but also a process that cannot be clearly distinguished from other processes, as long as the intended purpose of the process is achieved.

[0015] [Ink for forming coating film for optical components] The ink for forming a coating film for optical components (hereinafter, simply referred to as "ink") according to the first and second aspects of the present disclosure will be described below. The first and second aspects may have overlapping portions, i.e. the ink of the first aspect may have characteristics of the ink of the second aspect.

[0016] <First aspect> The ink according to the first aspect is The ink contains a black pigment, at least one of a colored pigment and a colorless pigment, a binder, and a volatile component, When the coating film for optical components (hereinafter also simply referred to as "coating film") is used, the coating film for optical components has an average refractive index n of 1.60 or more in a wavelength range of 400 nm to 700 nm, an average extinction coefficient k of 0.10 to 0.15 in a wavelength range of 400 nm to 700 nm, and a total volume ratio of the black pigment, the colored pigment, and the colorless pigment to the total volume of the coating film for optical components is 10 volume % to 40 volume %. This is an ink for forming a coating film on an optical component.

[0017] The ink according to the first embodiment can form a coating film for optical components that is excellent in light blocking properties, internal reflection suppression properties, refractive index, and film quality.

[0018] The light-blocking effect is obtained when the total ratio of the black pigment, colored pigment, and colorless pigment to the total volume of the coating film is 10 volume % or more, and when the average extinction coefficient k is 0.10 or more. Since the ink according to the first aspect can form a coating film for optical components with excellent light-blocking properties, the thickness of the coating film for optical components can be made thin and the variation in thickness can be reduced, thereby improving the positional accuracy of the optical component when it is incorporated into a lens case. The effect of suppressing internal reflection is obtained when the average refractive index n is 1.60 or more and the average extinction coefficient k is 0.15 or less. The effect of the refractive index is obtained by having an average refractive index n of 1.60 or more. The effect of the film quality is obtained by making the total ratio of the black pigment, the colored pigment, and the colorless pigment to the total volume of the coating film 40 volume % or less.

[0019] The coating films of the respective Examples have an average refractive index n of 1.60 or more and an average extinction coefficient k of 0.15 or less, and are therefore excellent in internal reflection suppression properties (that is, the ability to suppress internal reflection in optical components). The coating films of the examples have an average extinction coefficient k of 0.10 or more, and therefore have excellent light-shielding properties. This allows the coating film for optical components to be formed with a thin film thickness, which reduces film thickness variation and, as a result, improves the positional accuracy of the optical component when it is assembled into a lens case. The coating film of each Example has excellent light-blocking properties because the total ratio of the black pigment, colored pigment, and colorless pigment to the total volume of the coating film is 10 volume % or more (i.e., an average extinction coefficient k of 0.10 or more can be achieved; see Tables 1 to 3). The coating films of the respective Examples have excellent film quality (i.e., adhesion and solvent resistance) because the combined ratio of black pigment, colored pigment, and colorless pigment to the total volume of the coating film is 40 volume % or less (see Tables 1 to 3).

[0020] The ink according to the first embodiment will be described in more detail below.

[0021] <Average refractive index n of coating film for optical components> When the ink according to the first embodiment is used for a coating film for optical members, the coating film for optical members has an average refractive index n of 1.60 or more in the wavelength region of 400 nm to 700 nm. The average refractive index n of the coating film for optical components of 1.60 or more contributes to improving the internal reflection suppression property of the coating film for optical components (that is, the performance of suppressing internal reflection within the optical component).

[0022] From the viewpoint of further improving the internal reflection suppression property of the coating film, the average refractive index n of the coating film is preferably 1.70 or more.

[0023] On the other hand, from the viewpoint of further improving the internal reflection suppression property of the coating film, the average refractive index n of the coating film is preferably 1.90 or less, and more preferably 1.85 or less.

[0024] In the present disclosure, the phrase "when the ink is used as a coating film for optical components" means that the ink is applied and dried by heating to form a coating film. In the present disclosure, the average refractive index n and the average extinction coefficient k, as well as the total volume ratio of the black pigment, the colored pigment, and the colorless pigment to the total volume of the coating film for optical components, are all within the range of 0.02 g / m 2 The values ​​are measured using a coating film formed under heating and drying conditions of 70°C for 2 hours with a film thickness of 20 μm.

[0025] Preferred ranges for the average refractive index n include a range of 1.60 to 1.90 and a range of 1.70 to 1.85.

[0026] The average refractive index n of the coating film for optical members in the wavelength region of 400 nm to 700 nm is measured by the following method. Using a spectroscopic ellipsometer (e.g., J.A. Woollam Japan's High-Speed ​​Spectroscopic Ellipsometer M-2000), the refractive index of the coating film for optical components is measured in 10 nm increments in the wavelength range of 400 nm to 700 nm, and the arithmetic mean value of the measured refractive indexes is defined as the average refractive index n.

[0027] <Average extinction coefficient k of coating film for optical components> When the ink according to the first embodiment is used to form a coating film for optical members, the coating film for optical members has an average extinction coefficient k of 0.10 to 0.15.

[0028] The average extinction coefficient k of 0.10 or more contributes to the light-shielding effect of the coating film for optical components, which allows the coating film for optical components to be made thin and the thickness variation to be suppressed, thereby improving the positional accuracy when the optical components are assembled into optical component products. From the viewpoint of further improving the light blocking properties of the coating film for optical components, the average extinction coefficient k is preferably 0.11 or more.

[0029] The average extinction coefficient k of 0.15 or less contributes to improving the internal reflection suppression property of the coating film for optical components (that is, the performance of suppressing internal reflection within the optical component). From the viewpoint of further improving the internal reflection suppression property of the coating film for optical components, the average extinction coefficient k is preferably 0.14 or less, and more preferably 0.13 or less.

[0030] The average extinction coefficient k of the coating film for optical members in the wavelength region of 400 nm to 700 nm is measured by the following method. In the measurement of the refractive index to obtain the average refractive index n, the extinction coefficient of the coating film for optical components is obtained in 10 nm increments in the wavelength range of 400 nm to 700 nm by performing data analysis using the coating film for optical components as a Cauchy model. The arithmetic mean value of the obtained extinction coefficients is defined as the average extinction coefficient k.

[0031] <Total volume ratio of black pigment, colored pigment, and colorless pigment in the total volume of the coating film for optical components> When the ink according to the first embodiment is used as a coating film for optical components, the total volume ratio of the black pigment, colored pigment, and colorless pigment to the total volume of the coating film for optical components is 10 volume % to 40 volume %.

[0032] A volume ratio of 10 volume % or more contributes to improving the light blocking properties of the coating film (specifically, achieving an average extinction coefficient k of 0.10 or more of the coating film).

[0033] A volume ratio of 40 volume % or less contributes to improving the film quality (for example, adhesion and solvent resistance) of the coating film. From the viewpoint of further improving the film quality of the coating film, the above volume ratio is preferably 35 vol % or less, more preferably 30 vol % or less, and even more preferably 20 vol % or less.

[0034] The total volume ratio of the black pigment, colored pigment, and colorless pigment to the total volume of the coating film for optical components is determined based on the total volume of the ink coating film and the density of each pigment. The same applies to the contents of individual pigments described below.

[0035] The volume ratio of the black pigment to the total volume of the coating film for optical members is preferably 2 volume % to 20 volume %, preferably 3 volume % to 15 volume %, and preferably 5 volume % to 10 volume %.

[0036] The volume ratio of pigments other than black pigments (i.e., colored pigments and colorless pigments; the same applies below) to the total volume of the coating film for optical components is preferably 1 volume % to 31 volume %, preferably 1 volume % to 10 volume %, and preferably 1 volume % to 5 volume %.

[0037] In the coating film for optical components, the volume ratio of the black pigment to the total of the black pigment, colored pigment, and colorless pigment is preferably 20 volume% to 95 volume%, more preferably 40 volume% to 95 volume%, even more preferably 50 volume% to 95 volume%, and even more preferably 60 volume% to 90 volume%.

[0038] In the ink related to the first embodiment, the preferred range of the volume ratio of the black pigment to the total of the black pigment, colored pigment, and colorless pigment is the same as the preferred range of the volume ratio of the black pigment to the total of the black pigment, colored pigment, and colorless pigment in the coating film for optical components described above.

[0039] Hereinafter, each component that may be contained in the ink according to the first embodiment will be described.

[0040] <Black pigment> The ink according to the first embodiment contains at least one type of black pigment. The black pigment contributes to the coating having an average extinction coefficient k of 0.10 or more.

[0041] The black pigment preferably has an average refractive index n of 2.00 or more in the wavelength region of 400 nm to 700 nm. This makes it easier to achieve an average refractive index n of the coating film of 1.60 or more.

[0042] The black pigment preferably has an average extinction coefficient k of 0.10 or more in the wavelength region of 400 nm to 700 nm. This makes it easier to achieve an average extinction coefficient k of the coating film of 0.10 or more.

[0043] The black pigment preferably contains at least one selected from the group consisting of carbon black and titanium carbide. This makes it easier to achieve an average extinction coefficient k of the coating film of 0.10 or more.

[0044] When the black pigment contains at least one selected from the group consisting of carbon black and titanium carbide, the total proportion of the carbon black and titanium carbide in the black pigment is preferably 50 mass% or more, more preferably 60 mass% or more, and even more preferably 80 mass% or more.

[0045] Regarding carbon black as a black pigment, known carbon blacks described in known documents such as JP-A-2013-047311, JP-A-2013-047312, and JP-A-2013-185135 can be used.

[0046] As for titanium carbide as a black pigment, known titanium carbides described in known documents such as JP 2019-151786 A and JP 2016-122101 A can be used.

[0047] The black pigment preferably comprises carbon black. This makes it easier to achieve an average extinction coefficient k of the coating film of 0.10 or more.

[0048] When the black pigment contains carbon black, the proportion of carbon black in the black pigment is preferably 50% by mass or more, more preferably 60% by mass or more, and even more preferably 80% by mass or more.

[0049] The content of the black pigment in the ink according to the first embodiment is preferably 3.0% by mass to 20.0% by mass, more preferably 4.0% by mass to 16.0% by mass, and even more preferably 5.0% by mass to 10.0% by mass, relative to the total amount of the ink.

[0050] In the ink related to the first embodiment, the proportion of the black pigment in the total of the black pigment, colored pigment, and colorless pigment is preferably 10% by mass to 90% by mass, more preferably 20% by mass to 90% by mass, even more preferably 30% by mass to 90% by mass, and even more preferably 40% by volume to 90% by volume.

[0051] <Pigments other than black pigments (colored pigments, colorless pigments)> The ink according to the first embodiment contains at least one of a colored pigment and a colorless pigment (also referred to in the present disclosure as a "pigment other than a black pigment"). Pigments other than the black pigment contribute to the internal reflection suppression property of the coating film (specifically, the average extinction coefficient k of the coating film is 0.15 or less).

[0052] The colored pigment and the colorless pigment each preferably have an average refractive index n of 2.00 or more in the wavelength region of 400 nm to 700 nm. This makes it easier to achieve an average refractive index n of the coating film of 1.60 or more.

[0053] The colored pigment preferably has an average extinction coefficient k of 0.10 or more in the wavelength region of 400 nm to 700 nm. This makes it easier to achieve an average extinction coefficient k of the coating film of 0.10 or more.

[0054] The colored pigment preferably contains at least one selected from the group consisting of iron(III) oxide, silicon carbide, and copper(I) oxide.

[0055] When the colored pigment contains at least one selected from the group consisting of iron (III) oxide, silicon carbide, and copper (I) oxide, the total proportion of iron (III) oxide, silicon carbide, and copper (I) oxide in the colored pigment is preferably 50 mass % or more, more preferably 60 mass % or more, and even more preferably 80 mass % or more.

[0056] For colored pigments, known documents such as JP2016-37565A, JP2017-160425A, and JP2016-160124A can be referenced as appropriate.

[0057] The colorless pigment preferably includes at least one selected from the group consisting of titanium oxide, diamond, zirconia, and indium tin oxide.

[0058] When the colorless pigment contains at least one selected from the group consisting of titanium oxide, diamond, zirconia, and indium tin oxide, the total proportion of titanium oxide, diamond, zirconia, and indium tin oxide in the colorless pigment is preferably 50 mass% or more, more preferably 60 mass% or more, and even more preferably 80 mass% or more.

[0059] For colorless pigments, known documents such as JP-A-2022-182031 and JP-A-2023-104069 can be appropriately referred to.

[0060] From the viewpoint of the color of the coating film (preferably black, more preferably jet black), it is preferable that the pigment other than the black pigment contains a colorless pigment. In this case, the proportion of the colorless pigment in the pigments other than the black pigment is preferably 50% by mass or more, more preferably 60% by mass or more, and even more preferably 80% by mass or more.

[0061] The content of pigments other than the black pigment in the ink according to the first embodiment is preferably 1.0% by mass to 25.0% by mass, more preferably 1.0% by mass to 10.0% by mass, and even more preferably 1.5% by mass to 10.0% by mass, relative to the total amount of the ink.

[0062] <Total mass ratio of black pigment, colored pigment, and colorless pigment> The total mass ratio of the black pigment, colored pigment, and colorless pigment to the total solid content of the ink related to the first embodiment is preferably 6.5 mass% to 25.8 mass%, more preferably 7.0 mass% to 25.0 mass%, and even more preferably 8.0 mass% to 20.0 mass%. Here, the total solid content means all components excluding volatile components.

[0063] <Median diameter of pigment> In the ink according to the first embodiment, the median diameter (D50) of the pigment is preferably 100 nm or less. In this disclosure, the median diameter (D50) of the pigment means the median diameter of all pigments (black pigment, colored pigment, and colorless pigment) contained in the ink. In the present disclosure, the median diameter (D50) of a pigment is determined by the following method. 20 μL of the ink to be measured is diluted with 780 μL of propyl acetate to prepare a diluted solution for measuring the median diameter. The scattering intensity distribution frequency of the obtained diluted solution is measured at a measurement temperature of 20°C using a nanoSAQLA sample nanoparticle diameter measurement system manufactured by Otsuka Electronics Co., Ltd., and the median diameter (D50) is calculated based on the obtained scattering intensity distribution frequency.

[0064] The median diameter (D50) of the pigment is more preferably 70 nm or less, and even more preferably 50 nm or less. The lower limit of the median diameter (D50) of the pigment is, for example, 10 nm.

[0065] <Binder> The ink according to the first embodiment contains at least one type of binder. The binder contributes to the film-forming properties when forming an ink coating film, and further contributes to the film quality of the ink coating film.

[0066] As the binder, a known resin can be used. The binder is preferably an epoxy resin, more preferably a fluorene-based epoxy resin or a bisphenol A type epoxy resin, and further preferably a fluorene-based epoxy resin.

[0067] The content of the binder (for example, epoxy resin) in the ink according to the first embodiment is preferably 0.3% by mass to 40% by mass, more preferably 10% by mass to 35% by mass, and even more preferably 10% by mass to 30% by mass, relative to the total amount of the ink.

[0068] The binder preferably contains at least one resin having an average refractive index n of 1.50 or more in the wavelength region of 400 nm to 700 nm. This makes it easier to achieve an average refractive index n of the coating film of 1.60 or more.

[0069] More preferably, the binder contains at least one epoxy resin (hereinafter also referred to as "epoxy resin A") having an average refractive index n of 1.60 or more in the wavelength region of 400 nm to 700 nm. This makes it easier to achieve an average refractive index n of the coating film of 1.60 or more.

[0070] The proportion of the epoxy resin A in the binder is preferably 50% by mass or more, more preferably 60% by mass or more, and even more preferably 80% by mass or more.

[0071] The epoxy resin A preferably contains a fluorene-based epoxy resin.

[0072] The epoxy resin A preferably contains a thermosetting epoxy resin, and more preferably contains a fluorene-based epoxy resin, which is a thermosetting epoxy resin.

[0073] When the ink according to the first embodiment contains an epoxy resin (e.g., epoxy resin A), the ink according to the first embodiment preferably further contains a thiol-based curing agent as a curing agent for the epoxy resin, and more preferably further contains a thiol-based curing agent as a curing agent for the epoxy resin, and a tertiary amine as a curing accelerator. When the ink according to the first aspect contains a thiol-based curing agent as a curing agent for epoxy resin, the ink has excellent film-forming properties when forming an ink coating (particularly when heated at a relatively low temperature condition, such as 70° C. or lower).

[0074] An example of a thiol-based curing agent is jER Cure QX40 manufactured by Mitsubishi Chemical Corporation.

[0075] For thiol-based curing agents, publicly known documents such as JP2019-210325A and JP2016-75845A can be referenced as appropriate.

[0076] The content of the thiol-based curing agent relative to the total amount of the ink is preferably 0.2% by mass to 20.0% by mass, more preferably 1.0% by mass to 20.0% by mass, even more preferably 2.0% by mass to 20.0% by mass, and still more preferably 5.0% by mass to 20.0% by mass.

[0077] An example of the tertiary amine used as the curing accelerator is DMP-30 (2,4,6-tris(dimethylaminomethyl)phenol) manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.

[0078] For tertiary amines as curing accelerators, publicly known documents such as JP-A-2015-67832 and JP-A-2021-187910 can be referred to as appropriate.

[0079] The content of the tertiary amine as a curing accelerator is preferably 0.1% by mass to 10.0% by mass, and more preferably 1.0% by mass to 5.0% by mass, relative to the total amount of the ink.

[0080] <Volatile components> The ink according to the first embodiment contains at least one volatile component. The content of volatile components is preferably 50% by mass or more, more preferably 55% by mass or more, and even more preferably 60% by mass or more, based on the total amount of the ink.

[0081] The volatile component preferably contains an organic solvent, more preferably contains an organic solvent having a boiling point of 180° C. or lower. When the volatile component contains an organic solvent having a boiling point of 180° C. or less, the ink has excellent film-forming properties when forming a coating film (particularly when heated at a relatively low temperature such as 70° C. or less). The proportion of organic solvents having a boiling point of 180° C. or less in the organic solvents as volatile components is preferably 50% by mass or more, more preferably 60% by mass or more, and even more preferably 80% by mass or more.

[0082] In this disclosure, "boiling point" means the boiling point at atmospheric pressure.

[0083] The volatile component preferably contains at least one selected from the group consisting of propyl acetate, propylene glycol methyl ether acetate, propylene glycol monomethyl ether acetate, propylene glycol monomethyl ether, toluene, cyclohexane, and ethylene glycol monobutyl ether. All of these are organic solvents with boiling points of 180°C or less.

[0084] In addition to the above examples, organic solvents having a boiling point of 180° C. or less include ethanol, isopropyl alcohol, ethyl acetate, isobutyl acetate, butyl acetate, methyl ethyl ketone, methyl isobutyl ketone, xylene, acetone, ethyl cellosolve, ether, hexane, 1-butanol, methylcyclohexane, ethylcyclohexane, isohexane, butyl cellosolve, 1-butoxy-2-propanol, trichloroethylene, perchloroethylene, methanol, cellosolve acetate, mineral spirits, tetrahydrofuran, dioxane, ethyl lactate, and the like.

[0085] The ink according to the first embodiment may contain an organic solvent having a boiling point of more than 180°C. Examples of organic solvents having a boiling point of more than 180° C. include γ-butyrolactone, diethylene glycol diethyl ether, and the like.

[0086] <Silane coupling agent> The ink according to the first embodiment may contain at least one silane coupling agent. When the ink according to the first aspect contains a silane coupling agent, the adhesion of the coating film to the optical member, the hardness of the coating film, and the solvent resistance of the coating film are further improved.

[0087] The silane coupling agent is preferably a silane compound containing a functional group A which is at least one selected from the group consisting of an epoxy group, an amino group, a mercapto group, and an isocyanate group. The silane coupling agent contains the functional group A, and thus has excellent bonding strength with the binder. The silane coupling agent containing the functional group A may further contain an alkoxy group (preferably a methoxy group, an ethoxy group, etc.) from the viewpoint of the bondability with the optical member.

[0088] Specific examples of the silane coupling agent include, for example, 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, 3-glycidoxypropyltriethoxysilane, 8-glycidoxyoctyltrimethoxysilane, 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, Aminoethylaminopropyltrimethoxysilane, 3-aminoethylaminopropyltrimethoxysilane, 3-isocyanatopropyltriethoxysilane, 3-mercaptopropyltrimethoxysilane, and 3-Mercaptopropylmethyldimethoxysilane Examples include: Specific examples of the silane coupling agent include organosilanes containing a functional group A other than the specific examples mentioned above.

[0089] As the silane coupling agent, commercially available products can also be used. Commercially available examples of 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane include KBM-303 manufactured by Shin-Etsu Chemical Co., Ltd., and DOWSIL® Z-6043 Silane manufactured by Dow Corning Toray Co., Ltd. Commercially available examples of 3-glycidoxypropyltrimethoxysilane include KBM-403 manufactured by Shin-Etsu Chemical Co., Ltd., and DOWSIL® Z-6040 Silane manufactured by Dow Corning Toray Co., Ltd. An example of a commercially available product of 3-glycidoxypropylmethyldimethoxysilane is KBM-402 manufactured by Shin-Etsu Chemical Co., Ltd. An example of a commercially available product of 3-glycidoxypropylmethyldiethoxysilane is KBE-402 manufactured by Shin-Etsu Chemical Co., Ltd. An example of a commercially available product of 3-glycidoxypropyltriethoxysilane is KBE-403 manufactured by Shin-Etsu Chemical Co., Ltd. An example of a commercially available product of 8-glycidoxyoctyltrimethoxysilane is KBM-4803 manufactured by Shin-Etsu Chemical Co., Ltd. Examples of commercially available organosilanes (excluding the specific examples described above) containing an epoxy group as the functional group A include X-12-981S manufactured by Shin-Etsu Chemical Co., Ltd. and X-12-984S manufactured by Shin-Etsu Chemical Co., Ltd.

[0090] An example of a commercially available product of 3-aminopropyltrimethoxysilane is KBM-903 manufactured by Shin-Etsu Chemical Co., Ltd. Commercially available examples of 3-aminopropyltriethoxysilane include KBE-903 manufactured by Shin-Etsu Chemical Co., Ltd., and DOWSIL® Z-6011 Silane manufactured by Dow Corning Toray Co., Ltd. An example of a commercially available product of aminoethylaminopropyltrimethoxysilane is DOWSIL (registered trademark) Z-6062 Silane manufactured by Dow Corning Toray Co., Ltd. An example of a commercially available product of 3-aminoethylaminopropyltrimethoxysilane is DOWSIL (registered trademark) Z-6094 Silane manufactured by Dow Corning Toray Co., Ltd. An example of a commercially available organosilane (excluding the specific examples described above) containing an amino group as the functional group A is X-12-972F manufactured by Shin-Etsu Chemical Co., Ltd.

[0091] An example of a commercially available product of 3-isocyanatepropyltriethoxysilane is KBE-9007 manufactured by Shin-Etsu Chemical Co., Ltd. An example of a commercially available organosilane (excluding the specific examples described above) containing an isocyanate group as the functional group A is X-12-1159L manufactured by Shin-Etsu Chemical Co., Ltd.

[0092] Commercially available examples of 3-mercaptopropyltrimethoxysilane include KBM-803 manufactured by Shin-Etsu Chemical Co., Ltd., and DOWSIL® Z-6062 Silane manufactured by Dow Corning Toray Co., Ltd. An example of a commercially available product of 3-mercaptopropylmethyldimethoxysilane is KBM-802 manufactured by Shin-Etsu Chemical Co., Ltd. Examples of organosilanes (excluding the specific examples described above) containing a mercapto group as the functional group A include X-12-1154 manufactured by Shin-Etsu Chemical Co., Ltd. and X-12-1156 manufactured by Shin-Etsu Chemical Co., Ltd.

[0093] When the ink according to the first embodiment contains a silane coupling agent, the content of the silane coupling agent relative to the total amount of the binder in the ink according to the first embodiment is preferably 1% by mass to 50% by mass, more preferably 5% by mass to 30% by mass, and even more preferably 10% by mass to 25% by mass. When the content of the silane coupling agent is 1% by mass or more, the coating film formed is more excellent in adhesion to the optical member, hardness, and solvent resistance. When the content of the silane coupling agent is 50% by mass or less, the light-shielding property and refractive index of the formed coating film are superior.

[0094] <Filler> The ink according to the first embodiment may contain at least one type of filler. When the ink according to the first embodiment contains a filler, the gloss of the coating film that is formed is further suppressed.

[0095] The filler material may be an inorganic material, an organic material, or an inorganic-organic composite material. The filler may contain two or more materials. Examples of the filler include mica, silicone resin particles, silicone rubber particles, silicone resin / silicone rubber composite particles, urethane resin particles, acrylic resin particles, and urethane / acrylic composite resin particles.

[0096] The filler may be particles having an average primary particle size of 1 μm to 30 μm (preferably 2 μm to 30 μm). The filler may have any shape, such as a sphere or a flake. When the filler has a shape other than spherical, the particle size of the filler means the circle-equivalent diameter of the filler.

[0097] As the filler, commercially available products can also be used. Commercially available mica fillers include, for example: Mica manufactured by Yamaguchi Mica Co., Ltd. (product name A-11, average primary particle size 3 μm, flaky) Mica manufactured by Yamaguchi Mica Co., Ltd. (product name SJ-005, average primary particle size 5 μm, flaky) Mica manufactured by Yamaguchi Mica Co., Ltd. (product name TM-10, average primary particle size 11 μm, flaky) Mica manufactured by Yamaguchi Mica Co., Ltd. (product name A-21S, average primary particle size 22 μm, flaky), and Mica manufactured by Yamaguchi Mica Co., Ltd. (product name: SYA-21R, average primary particle size: 27 μm, flaky) Examples include:

[0098] Commercially available silicone resin particles as fillers include, for example: Silicone resin powder manufactured by Momentive Performance Materials (product name: Tospearl 120, average primary particle size 2 μm, spherical shape), Silicone resin powder manufactured by Shin-Etsu Chemical Co., Ltd. (product name: KPM-590, average primary particle size: 2 μm, spherical shape), Silicone resin powder manufactured by Shin-Etsu Chemical Co., Ltd. (product name: X-52-1620, average primary particle size: 5 μm, spherical shape), Silicone resin powder manufactured by Momentive Performance Materials (product name: Tospearl 2000B, average primary particle size 6 μm, spherical shape), and Silicone resin powder manufactured by Momentive Performance Materials (product name: Tospearl 1110, average primary particle size 11 μm, spherical) Examples include:

[0099] Examples of commercially available silicone rubber particles as fillers include: Silicone rubber powder manufactured by Shin-Etsu Chemical Co., Ltd. (product name: KMP-597, average primary particle size: 5 μm, spherical shape), Silicone rubber powder manufactured by Shin-Etsu Chemical Co., Ltd. (product name KMP-598, average primary particle size 13 μm, spherical shape), and Silicone rubber powder manufactured by Shin-Etsu Chemical Co., Ltd. (product name: KMP-402, average primary particle size: 30 μm, spherical) Examples include:

[0100] Examples of commercially available silicone resin / silicone rubber composite particles as fillers include: Silicone resin / silicone rubber composite powder manufactured by Shin-Etsu Chemical Co., Ltd. (product name KMP-605, average primary particle size 2 μm, spherical shape), Silicone resin / silicone rubber composite powder manufactured by Shin-Etsu Chemical Co., Ltd. (product name: KMP-600, average primary particle size: 5 μm, spherical shape), Silicone resin / silicone rubber composite powder manufactured by Shin-Etsu Chemical Co., Ltd. (product name KMP-601, average primary particle size 12 μm, spherical shape), and Silicone resin / silicone rubber composite powder manufactured by Shin-Etsu Chemical Co., Ltd. (product name KMP-602, average primary particle size 30 μm, spherical) Examples include:

[0101] An example of a commercially available urethane resin particle as a filler is urethane resin particle manufactured by Negami Chemical Industries, Ltd. (product name: U-600T, average primary particle diameter: 10 μm, spherical).

[0102] Commercially available acrylic resin particles as fillers include, for example, Acrylic resin particles manufactured by Negami Chemical Industries Co., Ltd. (product name G-800BK, average primary particle diameter 6 μm, spherical shape), and An example is acrylic resin particles manufactured by Negami Chemical Industries Co., Ltd. (product name G-400BK, average primary particle diameter 15 μm, spherical).

[0103] An example of a commercially available urethane / acrylic composite resin particle as a filler is urethane / acrylic composite resin particle manufactured by Negami Chemical Industrial Co., Ltd. (product name TE-812T, average primary particle diameter 6 μm, spherical).

[0104] When the ink according to the first embodiment contains a filler, the content of the filler relative to the total amount of the binder in the ink according to the first embodiment is preferably 1% by mass to 40% by mass, more preferably 2% by mass to 30% by mass, and even more preferably 5% by mass to 20% by mass. When the content of the filler is 1% by mass or more, the gloss of the coating film formed is further suppressed. When the filler content is 40% by mass or less, the color of the coating film formed is more excellent (for example, the amount of white spots in the coating film can be reduced).

[0105] <Other ingredients> The ink according to the first embodiment may contain other components in addition to those described above. For other components that may be contained, the descriptions in the aforementioned Patent Document 1 (JP Patent Publication No. 57-8264 A) and the aforementioned Patent Document 2 (JP Patent Publication No. 2012-149197 A) can be appropriately referred to.

[0106] <Ink according to the second aspect> The ink according to the second embodiment is The ink contains a black pigment, at least one of a colored pigment and a colorless pigment, a binder, and a volatile component, The black pigment, the colored pigment, and the colorless pigment each have an average refractive index n of 2.00 or more in a wavelength region of 400 nm to 700 nm, The black pigment and the colored pigment each have an average extinction coefficient k of 0.10 or more; The total mass ratio of the black pigment, the colored pigment, and the colorless pigment to the total solid content is 6.5 mass % to 25.8 mass %. Here, the total solid content means all components excluding volatile components.

[0107] The ink according to the second embodiment can form a coating film for optical components that is excellent in light blocking properties, internal reflection suppression properties, refractive index, and film quality.

[0108] The light-blocking effect is achieved when the combined proportion of the black pigment, colored pigment, and colorless pigment in the total solids content is 6.5 mass% or more, and when the black pigment and colored pigment each have an average extinction coefficient k of 0.10 or more. The effect of suppressing internal reflection is obtained when the average refractive index n is 1.60 or more and the ink contains at least one of a colored pigment and a colorless pigment. The effect of the refractive index is obtained when the black pigment, colored pigment, and colorless pigment each have an average refractive index n of 2.00 or more in the wavelength region of 400 nm to 700 nm. The effect of the film quality is obtained by making the total ratio of the black pigment, the colored pigment, and the colorless pigment in the total solid content 25.8 mass % or less.

[0109] Other preferred aspects of the ink of the second embodiment than the above-mentioned features are the same as those of the ink of the first embodiment described above.

[0110] [Coating film for optical components] The coating film for optical members according to the present disclosure is Contains a black pigment and at least one of a colored pigment and a colorless pigment, the average refractive index n in the wavelength range of 400 nm to 700 nm is 1.70 or more, the average extinction coefficient k in the wavelength range of 400 nm to 700 nm is 0.10 to 0.15, and the total ratio of the black pigment, the colored pigment, and the colorless pigment to the total volume is 10 volume % to 40 volume %; This is a coating for optical components.

[0111] According to the coating film for optical members of the present disclosure, the same effects as those of the ink according to the first embodiment described above can be obtained. A preferred embodiment of the coating film for optical members of the present disclosure is as described in the section "Ink for forming lens coating film."

[0112] [Optical Members] The optical member of the present disclosure comprises: A substrate for optical members, A coating film for optical members provided on a part (for example, an outer peripheral surface) of a substrate for optical members; Including, A coating film for an optical member contains a black pigment and at least one of a colored pigment and a colorless pigment, has an average refractive index n of 1.70 or more in a wavelength region of 400 nm to 700 nm, has an average extinction coefficient k of 0.10 to 0.15 in a wavelength region of 400 nm to 700 nm, and the total ratio of the black pigment, the colored pigment, and the colorless pigment to the total volume is 10 volume % to 40 volume %. It is an optical component.

[0113] According to the optical member of the present disclosure, the same effects as those of the ink according to the first embodiment described above can be obtained. A preferred embodiment of the coating film for optical members in the optical member of the present disclosure is as described in the section on the ink according to the first embodiment.

[0114] Substrates for optical members include glass substrates and plastic substrates. The method for measuring the average refractive index n in the wavelength region of 400 nm to 700 nm of the substrate for optical members and the preferred range thereof are the same as the method for measuring the average refractive index n in the wavelength region of 400 nm to 700 nm of the coating film for optical members and the preferred range thereof, which were explained in the section on the ink according to the first embodiment.

[0115] From the viewpoint of further improving the internal reflection suppression properties of the coating film for optical components, the absolute value of the difference between the average refractive index n of the substrate for optical components and the average refractive index n of the coating film for optical components is preferably 0.2 or less, more preferably 0.1 or less.

[0116] The outer diameter of the substrate for optical members is, for example, 1 mm to 300 mm, preferably 3 mm to 220 mm, and more preferably 10 mm to 150 mm. The thickness of the substrate for optical members is, for example, 0.5 mm to 30 mm, preferably 1 mm to 20 mm, and more preferably 2 mm to 15 mm.

[0117] Examples of optical members of the present disclosure include lenses, prisms, and waveguides. Examples of the substrate for an optical member of the present disclosure include a substrate for a lens, a substrate for a prism, and a substrate for a waveguide.

[0118] More specifically, examples of the optical components of the present disclosure include optical components for broadcasting, optical components for cinema, optical components for digital cameras, optical components for industrial cameras, optical components for projectors, optical components for car-mounted cameras, optical components for smartphone-mounted cameras, optical components using prisms (e.g., binoculars, periscopes, etc.), optical components using optical waveguides (e.g., smart glasses, etc.), and the like. EXAMPLES

[0119] Examples of the present disclosure will be described below, but the present disclosure is not limited to the following examples.

[0120] [Examples 1 to 29, Comparative Examples 1 to 4] <Ink Preparation> Inks containing the components shown in Tables 1 to 3 were prepared. Specifically, the following components were used:

[0121] (Black pigment) Carbon black: Mitsubishi Chemical HCF#2650 Titanium carbide: EM Japan NP-TIC-2-100

[0122] (Colored pigments) Iron(III) oxide: Iron(III) oxide nanoparticles manufactured by the Rare Metal Materials Research Institute Silicon carbide: EM Japan NP-SIC-9-100 Copper(I) oxide: Copper(I) oxide nanoparticles manufactured by the Rare Metal Materials Research Institute

[0123] (colorless pigment) Titanium oxide: Ishihara Sangyo Kaisha, Ltd. TTO-55(B) Diamond: Tokyo Chemical Industry Co., Ltd. N1083 Zirconia: Zirconeo-Cp made by ITEC ITO: Indium Tin Oxide, Mitsubishi Materials Electronic Chemicals Co., Ltd. E-ITO

[0124] (binder) Fluorene-based epoxy resin: Osaka Gas Chemicals CG-500 Bisphenol A epoxy resin: Mitsubishi Chemical jER828

[0125] (hardening agent) Thiol-based curing agent: Mitsubishi Chemical jER Cure QX40 Modified amine-based hardener: Fujicure 7005 manufactured by T&K TOKA

[0126] (Cure accelerator) Tertiary amine: 2,4,6-tris(dimethylaminomethyl)phenol, Fujifilm Wako Pure Chemical DMP-30

[0127] (Dispersant) Lubrizol Solsperse 39000

[0128] (Organic solvent) Propyl acetate: Fujifilm Wako Pure Chemical Industries, Ltd. PGMEA: Propylene glycol monomethyl ether acetate, Fujifilm Wako Pure Chemical Industries, Ltd. PGME: Propylene glycol monomethyl ether, manufactured by Tokyo Chemical Industry Co., Ltd. Toluene: Fujifilm Wako Pure Chemical Industries, Ltd. Cyclohexane: Fujifilm Wako Pure Chemical Industries, Ltd. EGMBE: Ethylene glycol monobutyl ether, manufactured by Tokyo Chemical Industry Co., Ltd. ·DEGDEE … Diethylene glycol diethyl ether, Fujifilm Wako Pure Chemical Industries, Ltd. γ-Butyrolactone … Fujifilm Wako Pure Chemical Industries, Ltd.

[0129] The refractive index n and extinction coefficient k of each pigment, the refractive index n of each binder, and the boiling point (bp) of each organic solvent are as shown in Tables 1 to 3. Here, the refractive index n and the extinction coefficient k are the average refractive index and extinction coefficient in the wavelength range of 400 nm to 700 nm, respectively. The boiling point (bp) of each organic solvent is the boiling point (° C.) under atmospheric pressure.

[0130] <Formation of coating film> The ink was applied to one side of a glass substrate for evaluation (B-270 manufactured by Schott, thickness 2 mm). The glass substrate with the ink applied was placed in a thermostatic chamber and heated to cure the ink, thereby obtaining a coating film.

[0131] <Calculation of the volume ratio of all pigments to the total volume of the coating> Ink is used, coating amount 0.02g / m 2 A coating film was formed under heating and drying conditions of 70°C for 2 hours with a film thickness of 20 μm. Based on the total volume of the resulting coating and the density of each pigment, The volume percentage of all pigments in the total volume of the coating (volume %), The volume percentage (volume%) of the black pigment in the total volume of the coating film, and The volume percentage (volume %) of pigments other than black pigments (i.e., colored pigments and colorless pigments) in the total volume of the coating film were calculated respectively. The results are shown in Tables 1 to 3.

[0132] <Measurement of the average refractive index n and average extinction coefficient k of the coating film in the wavelength range of 400 nm to 700 nm> Ink is used, coating amount 0.02g / m 2 A coating film was formed under heating and drying conditions of 70°C for 2 hours with a film thickness of 20 μm. For the resulting coating film, the average refractive index n and the average extinction coefficient k in the wavelength region of 400 nm to 700 nm were measured. These measurements were carried out using a J.A. Woollam Japan high-speed spectroscopic ellipsometer M-2000.

[0133] <Evaluation of the color of the coating> The color of the coating film whose average refractive index n and average extinction coefficient k were measured was visually confirmed. The results are shown in Tables 1 to 3. It is particularly preferable that the coating film has a jet black color.

[0134] <Evaluation of coating film quality (adhesion)> Ink is used, coating amount 0.02g / m 2 A coating film for evaluating adhesion was formed under heating and drying conditions of 70°C for 2 hours with a film thickness of 20 μm. A crosshatch test was carried out on the coating film for adhesion evaluation in accordance with ISO2409 (cross-cut method), and the adhesion of the coating film (i.e., adhesion to the glass substrate) was evaluated according to the following evaluation criteria: In this crosshatch test, the cut interval was set to 1 mm, and a grid of 25 squares with a side length of 1 mm was formed. The results are shown in Tables 1 to 3. In the following evaluation criteria, the most excellent coating film adhesion is ranked A.

[0135] -Evaluation criteria for coating adhesion- A: Of 25 grids, 0 grids were peeled off. B: Of 25 grids, 1 or 2 were peeled off. C: Of 25 grids, 3 or more grids were peeled off. D: The film-forming properties were insufficient, the film did not form, and evaluation was not possible.

[0136] <Evaluation of coating film quality (solvent resistance)> Ink is used, coating amount 0.02g / m 2 A coating film for evaluating solvent resistance was formed under heating and drying conditions of 70°C for 2 hours with a film thickness of 20 µm. The surface of the coating film for evaluating the solvent resistance was rubbed with a cotton swab soaked in isopropyl alcohol, and it was visually confirmed whether the color of the coating film was transferred to the cotton swab. The solvent resistance of the coating film was evaluated according to the following evaluation criteria. In the following evaluation criteria, the most excellent solvent resistance of the coating film is ranked A. The results are shown in Tables 1 to 3.

[0137] -Evaluation criteria for solvent resistance of coating film- A: Even after rubbing the cotton swab back and forth 20 times, no paint film color was found to adhere to the cotton swab. B: Even after rubbing the cotton swab back and forth 10 times, no paint film color was found to adhere to the cotton swab. However, between rubbing back and forth 11 and 20 times, paint film color was found to adhere to the cotton swab. C: The color of the coating was observed to adhere to the cotton swab between the 1st and 10th strokes. D: The film-forming properties were insufficient, the film did not form, and evaluation was not possible.

[0138] [Table 1]

[0139] [Table 2]

[0140] [Table 3]

[0141] As shown in Tables 1 to 3, the inks of each Example contained a black pigment, at least one of a colored pigment and a colorless pigment, and a binder, and when formed into a coating film, the coating film for optical components had an average refractive index n of 1.60 or more in the wavelength range of 400 nm to 700 nm, an average extinction coefficient k of 0.10 to 0.15, and the total ratio of the black pigment, colored pigment, and colorless pigment to the total volume of the coating film was 10 vol. % to 40 vol. %.

[0142] The coating films of the respective Examples have an average refractive index n of 1.60 or more and an average extinction coefficient k of 0.15 or less, and therefore have excellent internal reflection suppression properties (i.e., the ability to suppress internal reflection in optical components) when used as coating films for high refractive index optical components. The coating films of the examples have an average extinction coefficient k of 0.10 or more, and therefore have excellent light-shielding properties. This allows the coating film for optical components to be formed with a thin film thickness, which reduces film thickness variation and, as a result, improves the positional accuracy of the optical component when it is assembled into a lens case. The coating film of each Example has excellent light-blocking properties because the total ratio of the black pigment, colored pigment, and colorless pigment to the total volume of the coating film is 10 volume % or more (i.e., an average extinction coefficient k of 0.10 or more can be achieved; see Tables 1 to 3). The coating films of the respective Examples have excellent film quality (i.e., adhesion and solvent resistance) because the combined ratio of black pigment, colored pigment, and colorless pigment to the total volume of the coating film is 40 volume % or less (see Tables 1 to 3).

[0143] The results of the comparative examples compared to the respective examples were as follows. In Comparative Example 1, in which the total ratio of the black pigment, colored pigment, and colorless pigment to the total volume of the coating film was less than 10 volume %, the average extinction coefficient k was less than 0.10, and the light blocking properties were reduced. In Comparative Example 2, where the total ratio of the black pigment, colored pigment, and colorless pigment to the total volume of the coating film was more than 40 volume %, the coating film quality was insufficient (more specifically, the film-forming ability was insufficient and the film did not function properly).The reason for this is thought to be the relative insufficiency of the amount of binder. The coating films of Comparative Examples 3 and 4, which used inks containing a black pigment but neither a colored pigment nor a colorless pigment, had an average extinction coefficient k of more than 0.15, and the internal reflection suppression property was reduced.

[0144] Among Examples 1 to 29, in Examples 1 to 21 and 27 to 29 in which the binder contained an epoxy resin with an average refractive index n of 1.60 or more, the average refractive index n of the coating film was improved to 1.70 or more.

[0145] Of Examples 1 and 27, Example 1, in which a thiol-based curing agent was used as the curing agent for the epoxy resin, exhibited superior film quality of the coating film under low-temperature (70° C. or lower) heating and drying conditions.

[0146] Among Examples 1, 28, and 29, Example 1, in which the volatile components contained an organic solvent having a boiling point of 180° C. or less, exhibited superior film quality of the coating film under low temperature (70° C. or less) heating and drying conditions.

[0147] [Examples 101 to 104] The same operations (including various evaluations) as in Example 1 were performed, except that the silane coupling agent and filler were added to the ink components in the amounts shown in Table 4, and the amount of organic solvent was adjusted to the amount shown in Table 4. The results are shown in Table 4.

[0148] As the silane coupling agent, 3-glycidoxypropyltrimethoxysilane (KBM-403 manufactured by Shin-Etsu Chemical Co., Ltd.) was used. As the filler, silicone resin powder X-52-1621 (average particle size 5 μm) manufactured by Shin-Etsu Chemical Co., Ltd. was used. Table 4 also shows the results of Example 1 described above for comparison.

[0149] <Coating film evaluation 2> For each of the coating films obtained in Examples 101 to 104 and Example 1, the following coating film evaluation 2 was carried out. The coating film evaluation 2 includes the adhesion of the coating film 2, the solvent resistance of the coating film 2, the hardness of the coating film, the glossiness of the coating film, and the color tone of the coating film 2 (amount of white spots). The results are shown in Table 4.

[0150] (Adhesion of coating film 2) Ink is used, coating amount 0.02g / m 2 A coating film for evaluating adhesion was formed on the above-mentioned glass substrate under heating and drying conditions of 70° C.×2 hours and a film thickness of 20 μm. The adhesion between the obtained coating film and the glass substrate was measured according to the pull-off method (JIS K 5600-5-7:2014). Based on the obtained results, the adhesion 2 of the coating film was evaluated according to the following evaluation criteria. The most excellent rank for the adhesion 2 of the coating film is 3. -Evaluation criteria- 3: Maintains significant adhesion even after being exposed to a high temperature and humidity (85°C / 85%rh) environment for more than a week. 2: Maintains significant adhesion even after being exposed to a high temperature and high humidity (85°C / 85%rh) environment for less than one week (excluding the case of "3" above). 1: If not placed in a high temperature and high humidity (85℃·85%rh) environment, it retains significant adhesion.

[0151] (Solvent resistance of coating film 2) Ink is used, coating amount 0.02g / m 2 A coating film for evaluating solvent resistance was formed under heating and drying conditions of 70°C for 2 hours with a film thickness of 20 µm. The solvent resistance of the coating film for evaluating solvent resistance was evaluated using each of the solvents isopropyl alcohol (IPA), acetone, ethyl acetate, and methyl ethyl ketone (MEK). In detail, the surface of the coating film was rubbed back and forth 10 times with a 2 mm thick cotton swab soaked in each solvent under a load of 1 N, and visually confirmed whether the color of the coating film was transferred to the cotton swab. The solvent resistance 2 of the coating film was evaluated according to the following evaluation criteria. The most excellent rank for the solvent resistance 2 of the coating film is 3. -Evaluation criteria- 3: Ethyl acetate, MEK, acetone, and IPA all showed no color transfer to the cotton swab. 2: Color was observed to adhere to the cotton swab when using ethyl acetate and MEK, but no color was observed to adhere to the cotton swab when using IPA and acetone. 1: Ethyl acetate, MEK, and acetone caused color to adhere to the cotton swab, but IPA caused no color to adhere to the cotton swab. 0: Ethyl acetate, MEK, acetone, and IPA all caused color to adhere to the cotton swab.

[0152] (Coating film hardness) Ink is used, coating amount 0.02g / m 2 A coating film for hardness evaluation was formed under heating and drying conditions of 70°C for 2 hours with a film thickness of 20 μm. The coating was scratched by pressing a brass pointed part (acute angle 85°) with a load of 4 N while moving it at a speed of 70 mm / s, and the width of the scratch was measured. The narrower the scratch width, the higher the hardness. Based on the measurement results, the hardness of the coating film was evaluated according to the following evaluation criteria, with rank 3 being the most excellent hardness of the coating film. -Evaluation criteria- 3: The scratch width was less than 35 μm. 2: The scratch width was 35 μm or more and less than 40 μm. 1: The scratch width was 40 μm or more and less than 45 μm. 0: The scratch width was 45 μm or more.

[0153] (Glossiness of coating film) Ink is used, coating amount 0.02g / m 2 A coating film for evaluating gloss was formed under heating and drying conditions of 70°C for 2 hours with a film thickness of 20 µm. The "60 degree specular gloss Gs(60°)" of the obtained coating film was measured using a gloss meter IG-410 manufactured by HORIBA in accordance with JIS Z 8741-1997. The lower this value, the more suppressed the gloss.

[0154] (Paint color 2 (white spot amount)) Ink is used, coating amount 0.02g / m 2 A coating film for evaluating color 2 (amount of white spots) was formed under heating and drying conditions of 70°C for 2 hours with a film thickness of 20 μm. The coating film was observed through the glass substrate, and the color tone 2 of the coating film (specifically, the amount of white spots in the coating film) was evaluated based on the following evaluation criteria. -Evaluation criteria- 3: No white spots are visible 2: White spots are very slightly visible 1: White dots are visible 0: White dots are clearly visible

[0155] [Table 4]

[0156] As shown in Table 4, when the ink contained a silane coupling agent and a filler (Examples 101 to 104), as well as when the ink contained neither a silane coupling agent nor a filler (Example 1), the average refractive index n of the coating film was 1.60 or more, the average extinction coefficient k of the coating film was 0.10 to 0.15, and the ratio of the sum of all pigments to the total volume of the coating film was 10% by volume to 40% by volume. It was confirmed that the coating films of Examples 101 to 104, like the coating film of Example 1, were excellent in light blocking properties, internal reflection suppression properties, refractive index, and film quality. It was confirmed that the coating films of Examples 101 to 104 were superior in adhesion, solvent resistance, and hardness to the coating film of Example 1, and had a reduced gloss.

Claims

1. The ink contains a black pigment, at least one of a colored pigment and a colorless pigment, a binder, and a volatile component, When the coating film for optical components is used, the coating film for optical components has an average refractive index n of 1.60 or more in a wavelength region of 400 nm to 700 nm, an average extinction coefficient k of 0.10 to 0.15 in a wavelength region of 400 nm to 700 nm, and a total volume ratio of the black pigment, the colored pigment, and the colorless pigment to the total volume of the coating film for optical components is 10 volume % to 40 volume %. Ink for forming coatings on optical components.

2. 2. The ink for forming a coating film for optical members according to claim 1, wherein the coating film for optical members has an average refractive index n of 1.70 to 1.85 in a wavelength region of 400 nm to 700 nm.

3. the black pigment, the colored pigment, and the colorless pigment each have an average refractive index n of 2.00 or more in a wavelength region of 400 nm to 700 nm; 2. The ink for forming a coating film for an optical member according to claim 1, wherein the black pigment and the colored pigment each have an average extinction coefficient k of 0.10 or more.

4. The ink contains a black pigment, at least one of a colored pigment and a colorless pigment, a binder, and a volatile component, the black pigment, the colored pigment, and the colorless pigment each have an average refractive index n of 2.00 or more in a wavelength region of 400 nm to 700 nm; The black pigment and the colored pigment each have an average extinction coefficient k of 0.10 or more, The total mass ratio of the black pigment, the colored pigment, and the colorless pigment to the total solid content is 6.5% by mass to 25.8% by mass. Ink for forming coatings on optical components.

5. The black pigment comprises at least one selected from the group consisting of carbon black and titanium carbide, the color pigment comprises at least one selected from the group consisting of iron(III) oxide, silicon carbide, and copper(I) oxide; The colorless pigment includes at least one selected from the group consisting of titanium oxide, diamond, zirconia, and indium tin oxide. The ink for forming a coating film for an optical member according to claim 1 or 4.

6. The ink for forming a coating film for optical components according to claim 1 or 4, wherein the pigment has a median diameter of 100 nm or less.

7. 5. The ink for forming a coating film for an optical member according to claim 1, wherein the binder contains an epoxy resin having an average refractive index n of 1.60 or more in a wavelength region of 400 nm to 700 nm.

8. The ink for forming a coating film for an optical member according to claim 7 , wherein the epoxy resin comprises a fluorene-based epoxy resin.

9. The ink for forming a coating film for an optical member according to claim 7 , wherein the epoxy resin comprises a thermosetting epoxy resin.

10. The ink for forming a coating film for an optical member according to claim 9, further comprising a thiol-based curing agent as a curing agent for an epoxy resin, and a tertiary amine as a curing accelerator.

11. 5. The ink for forming a coating film for optical components according to claim 1, wherein the content of the volatile component is 50 mass % or more based on the total amount of the ink for optical components.

12. The ink for forming a coating film for an optical member according to claim 1 , wherein the volatile component comprises an organic solvent having a boiling point of 180° C. or less.

13. 5. The ink for forming a coating film for optical components according to claim 1, wherein the volatile component comprises at least one selected from the group consisting of propyl acetate, propylene glycol monomethyl ether acetate, propylene glycol monomethyl ether, toluene, cyclohexane, and ethylene glycol monobutyl ether.

14. The ink for forming a coating film for an optical member according to claim 1 or 4, further comprising a silane coupling agent.

15. The ink for forming a coating film for an optical member according to claim 1 or 4, further comprising a filler.

16. A substrate for optical members, A coating film for optical members provided on a part of the substrate for optical members; Equipped with the coating film for optical members contains a black pigment and at least one of a colored pigment and a colorless pigment, has an average refractive index n of 1.70 or more in a wavelength region of 400 nm to 700 nm, has an average extinction coefficient k of 0.10 to 0.15 in a wavelength region of 400 nm to 700 nm, and a total ratio of the black pigment, the colored pigment, and the colorless pigment to the total volume is 10 volume % to 40 volume %; Optical components.

17. The optical member according to claim 16, which is an optical member for broadcasting, an optical member for cinema, an optical member for digital cameras, an optical member for industrial cameras, an optical member for projectors, an optical member for car-mounted cameras, an optical member for smartphone-mounted cameras, an optical member using a prism, or an optical member using an optical waveguide.

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