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

Abstract

The present invention addresses the problem of providing: an ink for forming a coating film for an optical member, said ink being capable of forming a coating film for an optical member, said coating film having excellent light-blocking properties, inner surface reflection suppression properties, refractive index, and film quality; and an application thereof. Provided are: an ink for forming a coating film for an optical member, which contains a binder and a volatile component, at least one of a black pigment, a colored pigment and a colorless pigment, and which, when used as a coating film for an optical member, does not contain an organic solvent; the average refractive index (n) of the coating film for optical members in the wavelength range of 400-700 nm is 1.70 or more, the average extinction coefficient (k) of the coating film for optical members in the wavelength range of 400-700 nm is 0.10-0.15, and the ratio of the total of the black pigment, the colored pigment, and the colorless pigment to the total volume of the coating film for optical members is 10-40 vol%.

Description

Technical Field

[0001] The present invention relates to an ink for forming a coating film for an optical component and an optical component. Background Art

[0002] Conventionally, for the purpose of suppressing reflection on the inner surface of an optical component such as a lens, a step of applying a coating to a portion of the optical component to form a coating film (for example, sometimes referred to as "inking") has been performed.

[0003] For example, Patent Document 1 discloses an antireflection coating for inner surfaces 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 a high degree of blackness as a main pigment.

[0004] Furthermore, Patent Document 2 discloses the following inner surface anti-reflection black paint for optical elements, which has a sufficient inner surface anti-reflection effect on optical elements with a high refractive index and can ensure coating operability even when the paint is stored for a long time.

[0005] The inner surface anti-reflection black coating for optical elements disclosed in Patent Document 2 is characterized in that:

[0006] In an optical element inner surface antireflection black coating containing at least titanium dioxide, carbon black, a binder resin, a dispersant and a solvent,

[0007] The titanium dioxide has a methanol hydrophobization degree of 30% or more and 80% or less, a pH of 3.0 or more and 8.0 or less, and contains 35% by mass or more and 75% by mass or less of the solid content of the inner surface anti-reflection black coating for optical elements,

[0008] 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 contains 2% by mass or more and 20% by mass or less relative to the solid content of the inner surface anti-reflection black coating for optical elements,

[0009] The above dispersant is a dispersant obtained by using a phthalocyanine compound and a polymer dispersant in combination.

[0010] The phthalocyanine compound is contained in an amount of 1 mass % or more and 20 mass % or less based on 100 mass % of the carbon black,

[0011] 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% by mass or more and 40% by mass or less when the total of the titanium dioxide and the carbon black is 100% by mass.

[0012] Patent Document 1: Japanese Patent Application Laid-Open No. 57-8264

[0013] Patent Document 2: Japanese Patent Application Publication No. 2012-149197

[0014] In recent years, miniaturization and / or weight reduction have been accelerating for optical component products in which optical components (eg, lenses, prisms, waveguides, etc.) are assembled.

[0015] As one of the methods for miniaturizing and / or lightening optical component products, there is a method of using high refractive index optical components (e.g., optical components with a refractive index of 1.60 or more). According to the high refractive index optical components, the path of light can be greatly bent even at a small curvature. As a result, the optical components can be thinned and the number of optical components included in the overall optical component product can be reduced.

[0016] However, if the refractive index of the optical component increases and the angle of the bent light path increases, the amount of displacement of the focusing position relative to the assembly position of the optical component increases, resulting in a tendency for image quality to deteriorate.

[0017] In this regard, the outer peripheral surface of the optical component becomes the position reference of the optical component when the optical component is assembled into the frame. Therefore, the deviation of the film thickness of the optical component coating film provided on the outer peripheral surface of the optical component will affect the position accuracy of the optical component when the optical component is assembled into the frame.

[0018] In order to suppress the variation in the film thickness of the optical component coating film, the light shielding property of the optical component coating film is improved to reduce the film thickness of the optical component coating film, thereby effectively reducing the influence of the variation in the film thickness of the optical component coating film on the positional accuracy of the optical component.

[0019] As described above, from the viewpoint of improving the positional accuracy of the optical component when the optical component is assembled into a lens frame, it is sometimes desired that the light shielding property of the coating film for an optical component provided on the optical component be improved.

[0020] On the other hand, in coating films for optical components, it is sometimes desired to further improve the performance of suppressing internal surface reflection in optical components (hereinafter also referred to as internal surface reflection suppression property) and film quality (for example, adhesion, solvent resistance, etc.).

[0021] Furthermore, from the perspective of the internal surface reflection suppression of the coating for optical components, it is preferred from an optical principle that the refractive index of the substrate for optical components (e.g., a lens) and the refractive index of the coating for optical components provided on a portion of the substrate for optical components are set to values ​​that are extremely close (ideally the same value).

[0022] Therefore, when the refractive index of the optical component substrate is increased, it is preferable to increase the refractive index of the optical component coating film. Summary of the invention

[0023] The present invention has been accomplished in view of the above circumstances.

[0024] An embodiment of the present invention aims to provide an optical component coating film-forming ink capable of forming an optical component coating film having excellent light-shielding properties, inner surface reflection suppression properties, refractive index, and film quality, and an optical component having the optical component coating film.

[0025] The present invention includes the following aspects.

[0026] <1> An ink for forming a coating film for an optical component, comprising at least one of a black pigment, a colored pigment, and a colorless pigment, a binder, and a volatile component.

[0027] In the case of a coating film for optical components, the average refractive index n of the coating film for optical components in the wavelength range of 400nm to 700nm is greater than 1.60, the average extinction coefficient k of the coating film for optical components in the wavelength range of 400nm to 700nm is 0.10 to 0.15, and the volume ratio of the total of black pigment, colored pigment and colorless pigment in the total volume of the coating film for optical components is 10 volume % to 40 volume %.

[0028] <2> The coating film-forming ink for an optical component according to <1>, wherein

[0029] The average refractive index n of the coating film for optical components in the wavelength range of 400 nm to 700 nm is 1.70 to 1.85.

[0030] <3> The coating film-forming ink for an optical component according to <1> or <2>, wherein

[0031] The average refractive index n of the black pigment, the colored pigment, and the colorless pigment in the wavelength range of 400 nm to 700 nm is 2.00 or more.

[0032] The average extinction coefficient k of the black pigment and the color pigment is respectively 0.10 or more.

[0033] <4> An ink for forming a coating film for an optical component, comprising at least one of a black pigment, a colored pigment, and a colorless pigment, a binder, and a volatile component,

[0034] The average refractive index n of the black pigment, the colored pigment, and the colorless pigment in the wavelength range of 400 nm to 700 nm is 2.00 or more.

[0035] The average extinction coefficient k of black pigment and colored pigment is 0.10 or more.

[0036] The mass ratio of the total of the black pigment, the colored pigment, and the colorless pigment in the total solid content is 6.5% by mass to 25.8% by mass.

[0037] <5> The ink for forming a coating film for an optical component according to any one of <1> to <4>, wherein

[0038] The black pigment contains at least one selected from the group consisting of carbon black and titanium carbide,

[0039] The colored pigment includes at least one selected from the group consisting of iron (III) oxide, silicon carbide, and copper (I) oxide.

[0040] The colorless pigment includes at least one selected from the group consisting of titanium oxide, diamond, zirconium oxide, and indium tin oxide.

[0041] <6> The coating film-forming ink for an optical component according to any one of <1> to <5>, wherein

[0042] The median particle size of the pigment is 100 nm or less.

[0043] <7> The coating film-forming ink for an optical component according to any one of <1> to <6>, wherein

[0044] The adhesive contains an epoxy resin having an average refractive index n of 1.60 or more in a wavelength range of 400 nm to 700 nm.

[0045] <8> The coating film-forming ink for an optical component according to <7>, wherein

[0046] The epoxy resin includes a fluorene-based epoxy resin.

[0047] <9> The coating film-forming ink for optical components according to <7> or <8>, wherein

[0048] The epoxy resin includes a heat-curing epoxy resin.

[0049] <10> The coating film-forming ink for an optical component according to <9>, further comprising a thiol-based curing agent as a curing agent for the epoxy resin and a tertiary amine as a curing accelerator.

[0050] <11> The coating film-forming ink for an optical component according to any one of <1> to <10>, wherein

[0051] The content of the volatile component is 50% by mass or more based on the total amount of the ink for forming a coating film for an optical component.

[0052] <12> The coating film-forming ink for an optical component according to any one of <1> to <11>, wherein

[0053] The volatile component includes an organic solvent having a boiling point of 180° C. or lower.

[0054] <13> The coating film-forming ink for an optical component according to any one of <1> to <12>, wherein

[0055] 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.

[0056] <14> The coating-film-forming ink for an optical component according to any one of <1> to <13>, further comprising a silane coupling agent.

[0057] <15> The coating-film-forming ink for an optical component according to any one of <1> to <14>, further comprising a filler.

[0058] <16> An optical component comprising:

[0059] Substrates for optical components; and

[0060] Coating film for optical components, provided on a part of a substrate for optical components

[0061] The coating film for optical components 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 the wavelength range of 400 nm to 700 nm, and an average extinction coefficient k of 0.10 to 0.15 in the wavelength range of 400 nm to 700 nm.

[0062] The total amount of the black pigment, the colored pigment, and the colorless pigment in the total volume is 10% to 40% by volume.

[0063] <17> The optical component according to <16>, which is an optical component for broadcasting, an optical component for cinema, an optical component for a digital camera, an optical component for an industrial camera, an optical component for a projector, an optical component for a car camera, an optical component for a smartphone-mounted camera, an optical component using a prism, or an optical component using an optical waveguide.

[0064] Effects of the Invention

[0065] According to one embodiment of the present invention, there is provided an ink for forming an optical component coating film capable of forming an optical component coating film having excellent light-shielding properties, internal surface reflection suppression properties, refractive index and film quality, and an optical component having the optical component coating film. DETAILED DESCRIPTION

[0066] In the present specification, a numerical range expressed using "to" indicates a range including the numerical values ​​described before and after "to" as the minimum value and the maximum value, respectively.

[0067] In the numerical ranges recorded in stages in this specification, the upper limit or lower limit recorded in a certain numerical range can be replaced by the upper limit or lower limit of the numerical range recorded in other stages. In addition, in the numerical ranges recorded in this specification, the upper limit or lower limit recorded in a certain numerical range can be replaced by the value shown in the embodiments.

[0068] In the present specification, when a plurality of substances corresponding to each component are present in a composition, the amount of each component in the composition means the total amount of the plurality of substances present in the composition unless otherwise specified.

[0069] In the present specification, a combination of two or more preferred aspects is a more preferred aspect.

[0070] In the present 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 can be achieved.

[0071] [Ink for forming coating films for optical components]

[0072] Hereinafter, the coating film-forming ink for optical components according to the first aspect and the second aspect of the present invention (hereinafter, also simply referred to as “ink”) will be described.

[0073] The first aspect and the second aspect may have overlapping parts. That is, the ink of the first aspect may have the characteristics of the ink of the second aspect.

[0074] <<Method 1>>

[0075] The ink according to the first aspect is an ink for forming a coating film for an optical component, comprising at least one of a black pigment, a colored pigment, and a colorless pigment, a binder, and a volatile component.

[0076] In the case of a coating film for optical components (hereinafter also referred to as "coating film"), the average refractive index n of the coating film for optical components in the wavelength range of 400nm to 700nm is greater than 1.60, the average extinction coefficient k of the coating film for optical components in the wavelength range of 400nm to 700nm is 0.10 to 0.15, and the volume ratio of the total of black pigment, colored pigment and colorless pigment in the total volume of the coating film for optical components is 10 volume % to 40 volume %.

[0077] According to the ink according to the first aspect, a coating film for an optical component having excellent light-shielding properties, internal surface reflection suppression properties, refractive index, and film quality can be formed.

[0078] The light-shielding effect is obtained by making the total ratio of the black pigment, the colored pigment and the colorless pigment in the total volume of the coating film 10% by volume or more and the average extinction coefficient k being 0.10 or more. According to the ink involved in the first embodiment, a coating film for optical components with excellent light-shielding properties can be formed, so the film thickness of the coating film for optical components can be reduced and the deviation of the film thickness can be reduced, and as a result, the position accuracy of the optical components when the optical components are assembled into the frame can be improved.

[0079] The effect of suppressing inner surface reflection is an effect obtained by making the average refractive index n equal to or greater than 1.60 and the average extinction coefficient k equal to or less than 0.15.

[0080] The effect of the refractive index is an effect obtained by making the average refractive index n 1.60 or more.

[0081] The film quality effect is obtained by making the total ratio of the black pigment, the color pigment and the colorless pigment in the total volume of the coating film 40 volume % or less.

[0082] Since the coating film of each Example has an average refractive index n of 1.60 or more and an average extinction coefficient k of 0.15 or less, the coating film has excellent internal surface reflection suppression performance (that is, performance of suppressing internal surface reflection in an optical component).

[0083] The coatings of the examples have an average extinction coefficient k of 0.10 or more, which means that they have excellent light shielding properties. This allows the coatings for optical components to be formed with a thin film thickness, thereby reducing the variation in film thickness, and as a result, improving the positional accuracy of the optical components when they are assembled into a lens frame.

[0084] Since the total ratio of black pigment, color pigment and colorless pigment in the total volume of the coating film is 10 volume % or more, the coating film of each example has excellent light shielding property (that is, the average extinction coefficient k can be 0.10 or more; refer to Table 1 to Table 3).

[0085] Since the total ratio of the black pigment, the colored pigment and the colorless pigment in the total volume of the coating film is 40 volume % or less, the coating film of each example has excellent film quality (ie, adhesion and solvent resistance) (see Tables 1 to 3).

[0086] Hereinafter, the ink according to the first aspect will be described in more detail.

[0087] <Average refractive index n of coating films for optical components>

[0088] When the ink according to the first aspect is used as a coating film for an optical component, the coating film for an optical component has an average refractive index n of 1.60 or more in a wavelength range of 400 nm to 700 nm.

[0089] The average refractive index n of the coating film for an optical component of 1.60 or more contributes to improvement of the internal surface reflection suppression property of the coating film for an optical component (that is, the performance of suppressing internal surface reflection in an optical component).

[0090] From the viewpoint of further improving the inner surface reflection suppression property of the coating film, the average refractive index n of the coating film is preferably 1.70 or more.

[0091] On the other hand, from the viewpoint of further improving the inner surface 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.

[0092] In the present invention, when the ink is used "as a coating film for an optical component", it means when the ink is applied and heated and dried to form a coating film.

[0093] In the present invention, the average refractive index n and the average extinction coefficient k, as well as the volume ratio of the total of the black pigment, the color pigment and the colorless pigment in the total volume of the coating film for optical components are all expressed as the average refractive index n and the average extinction coefficient k when the coating amount is 0.02 g / m 2 , the value measured for a coating film formed under the conditions of heating and drying at 70°C for 2 hours and a film thickness of 20 μm.

[0094] Preferred ranges of the average refractive index n include a range of 1.60 to 1.90 and a range of 1.70 to 1.85.

[0095] The average refractive index n of the coating film for an optical component in the wavelength range of 400 nm to 700 nm is measured by the following method.

[0096] The refractive index of the coating film for optical components is measured using a spectroscopic ellipsometer (for example, high-speed spectroscopic ellipsometer M-2000 manufactured by JA Woollam Japan Co., Ltd.) in a wavelength range of 400 to 700 nm at 10 nm intervals, and the arithmetic mean of the measured refractive index values ​​is defined as the average refractive index n.

[0097] <Average extinction coefficient k of coatings for optical components>

[0098] When the ink according to the first aspect is used as a coating film for an optical component, the average extinction coefficient k of the coating film for an optical component is 0.10 to 0.15.

[0099] The average extinction coefficient k of 0.10 or more helps to improve the light shielding effect of the optical component coating film. As a result, the film thickness of the optical component coating film can be thinned, thereby suppressing the film thickness deviation, and as a result, it is possible to improve the position accuracy when assembling the optical component in the optical component product.

[0100] From the viewpoint of further improving the light shielding property of the coating film for an optical component, the average extinction coefficient k is preferably 0.11 or more.

[0101] An average extinction coefficient k of 0.15 or less contributes to improvement in the internal surface reflection suppressing property of the coating film for an optical component (that is, the performance of suppressing internal surface reflection in an optical component).

[0102] From the viewpoint of further improving the inner surface reflection suppression property of the coating film for an optical component, the average extinction coefficient k is preferably 0.14 or less, and more preferably 0.13 or less.

[0103] The average extinction coefficient k of the coating film for an optical component in the wavelength range of 400 nm to 700 nm is measured by the following method.

[0104] In the refractive index measurement for obtaining the above-mentioned average refractive index n, the extinction coefficient of the optical component coating film is obtained with a 10 nm scale for the wavelength range of 400 nm to 700 nm by performing data analysis using the optical component coating film as a Cauchy model. The arithmetic mean of the obtained extinction coefficients is set as the average extinction coefficient k.

[0105] <Volume ratio of the total of black pigment, color pigment and colorless pigment in the total volume of the coating film for optical components>

[0106] When the ink according to the first embodiment is used as a coating film for an optical component, the total volume ratio of the black pigment, the color pigment, and the colorless pigment in the total volume of the coating film for an optical component is 10 volume % to 40 volume %.

[0107] The volume ratio of 10 volume % or more contributes to improving the light shielding property of the coating film (specifically, achieving an average extinction coefficient k of the coating film of 0.10 or more).

[0108] The volume ratio being 40 volume % or less contributes to improvement of the film quality (for example, adhesion and solvent resistance) of the coating film.

[0109] From the viewpoint of further improving the film quality of the coating film, the volume ratio is preferably 35% by volume or less, more preferably 30% by volume or less, and even more preferably 20% by volume or less.

[0110] The volume ratio of the total of the black pigment, the colored pigment, and the colorless pigment in the total volume of the coating film for an optical component is determined based on the total volume of the ink coating film and the density of each pigment.

[0111] The same applies to the content of the individual pigments described later.

[0112] The volume ratio of the black pigment in the total volume of the coating film for optical components is preferably 2 to 20% by volume, more preferably 3 to 15% by volume, and even more preferably 5 to 10% by volume.

[0113] The volume ratio of pigments other than the black pigment (i.e., colored pigments and colorless pigments, the same applies hereinafter) in the total volume of the coating film for optical components is preferably 1% to 31% by volume, more preferably 1% to 10% by volume, and further preferably 1% to 5% by volume.

[0114] In the coating film for optical components, the volume ratio of the black pigment in the total of the black pigment, the colored pigment and the colorless pigment is preferably 20% to 95% by volume, more preferably 40% to 95% by volume, further preferably 50% to 95% by volume, further preferably 60% to 90% by volume.

[0115] The preferred range of the volume ratio of the black pigment in the ink involved in the first embodiment is the same as the preferred range of the volume ratio of the black pigment in the total of the black pigment, the colored pigment and the colorless pigment in the above-mentioned coating for optical components.

[0116] Hereinafter, each component that may be contained in the ink according to the first embodiment will be described.

[0117] <Black Pigment>

[0118] The ink according to the first aspect contains at least one black pigment.

[0119] The black pigment contributes to an average extinction coefficient k of the coating film being 0.10 or more.

[0120] The average refractive index n of the black pigment in the wavelength range of 400 nm to 700 nm is preferably 2.00 or more.

[0121] This makes it easier to achieve an average refractive index n of 1.60 or more for the coating film.

[0122] The average extinction coefficient k of the black pigment in the wavelength range of 400 nm to 700 nm is preferably 0.10 or more.

[0123] This makes it easier to achieve an average extinction coefficient k of 0.10 or more in the coating film.

[0124] The black pigment preferably includes at least one selected from the group consisting of carbon black and titanium carbide.

[0125] This makes it easier to achieve an average extinction coefficient k of 0.10 or more in the coating film.

[0126] When the black pigment contains at least one selected from the group consisting of carbon black and titanium carbide, the total proportion of 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.

[0127] As carbon black as a black pigment, known carbon black described in known documents such as JP-A-2013-047311, JP-A-2013-047312, and JP-A-2013-185135 can be used.

[0128] Regarding titanium carbide as a black pigment, known titanium carbide described in known documents such as JP-A-2019-151786 and JP-A-2016-122101 can be used.

[0129] The black pigment preferably comprises carbon black.

[0130] This makes it easier to achieve an average extinction coefficient k of 0.10 or more in the coating film.

[0131] 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.

[0132] The content of the black pigment in the ink according to the first aspect is preferably 3.0 to 20.0% by mass, more preferably 4.0 to 16.0% by mass, and even more preferably 5.0 to 10.0% by mass, relative to the total amount of the ink.

[0133] In the ink according to the first aspect, the proportion of the black pigment in the total of the black pigment, the colored pigment, and the colorless pigment is preferably 10% to 90% by mass, more preferably 20% to 90% by mass, further preferably 30% to 90% by mass, and further preferably 40% to 90% by volume.

[0134] <Pigments other than black pigments (colored pigments, colorless pigments)>

[0135] The ink according to the first aspect contains at least one of a colored pigment and a colorless pigment (also referred to as “a pigment other than a black pigment” in the present invention).

[0136] Pigments other than the black pigment contribute to the improvement of the inner surface reflection suppression property of the coating film (specifically, the average extinction coefficient k of the coating film is 0.15 or less).

[0137] It is preferred that the average refractive index n of each of the colored pigment and the colorless pigment in the wavelength range of 400 nm to 700 nm is 2.00 or more.

[0138] This makes it easier to achieve an average refractive index n of 1.60 or more for the coating film.

[0139] The average extinction coefficient k of the colored pigment in the wavelength range of 400 nm to 700 nm is preferably 0.10 or more.

[0140] This makes it easier to achieve an average extinction coefficient k of 0.10 or more in the coating film.

[0141] The colored pigment preferably contains at least one selected from the group consisting of iron (III) oxide, silicon carbide, and copper (I) oxide.

[0142] 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% by mass or more, more preferably 60% by mass or more, and even more preferably 80% by mass or more.

[0143] Regarding the colored pigment, known documents such as Japanese Patent Application Laid-Open No. 2016-37565, Japanese Patent Application Laid-Open No. 2017-160425, and Japanese Patent Application Laid-Open No. 2016-160124 can be referred to as appropriate.

[0144] The colorless pigment preferably contains at least one selected from the group consisting of titanium oxide, diamond, zirconium oxide, and indium tin oxide.

[0145] When the colorless pigment contains at least one selected from the group consisting of titanium oxide, diamond, zirconium oxide and indium tin oxide, the proportion of the total of titanium oxide, diamond, zirconium oxide and indium tin oxide in the colorless pigment is preferably 50 mass % or more, more preferably 60 mass % or more, and further preferably 80 mass % or more.

[0146] Regarding the colorless pigment, known documents such as Japanese Patent Application Laid-Open No. 2022-182031 and Japanese Patent Application Laid-Open No. 2023-104069 can be appropriately referred to.

[0147] From the viewpoint of the color tone (preferably black, more preferably jet black) of the coating film, the pigment other than the black pigment preferably contains a colorless pigment.

[0148] In this case, the ratio of the colorless pigment to 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.

[0149] The content of pigments other than the black pigment in the ink according to the first embodiment is preferably 1.0 to 25.0% by mass, more preferably 1.0 to 10.0% by mass, and even more preferably 1.5 to 10.0% by mass, relative to the total amount of the ink.

[0150] <Total mass ratio of black pigment, color pigment and colorless pigment>

[0151] The mass ratio of the total of the black pigment, the colored pigment, and the colorless pigment in the total solid content of the ink according to the first embodiment is preferably 6.5 to 25.8 mass %, more preferably 7.0 to 25.0 mass %, and even more preferably 8.0 to 20.0 mass %.

[0152] Here, the total solid content refers to all components except volatile components.

[0153] <Median particle size of pigment>

[0154] In the ink according to the first aspect, the median particle size (D50) of the pigment is preferably 100 nm or less.

[0155] In the present invention, the median particle size (D50) of the pigment refers to the median particle size of all the pigments (black pigment, color pigment, and colorless pigment) contained in the ink.

[0156] In the present invention, the median particle size (D50) of the pigment is determined by the following method.

[0157] 20 μL of the ink to be measured was diluted with 780 μL of propyl acetate to prepare a dilution solution for median particle size measurement. The scattering intensity distribution frequency of the obtained dilution solution was measured at a measurement temperature of 20°C using the multi-specimen nanoparticle size measurement system nanoSAQLA manufactured by Otsuka Electronics Co., Ltd., and the median particle size (D50) was calculated based on the obtained scattering intensity distribution frequency.

[0158] The median particle size (D50) of the pigment is more preferably 70 nm or less, and further preferably 50 nm or less.

[0159] The lower limit of the median particle size (D50) of the pigment is, for example, 10 nm.

[0160] <Adhesive>

[0161] The ink according to the first aspect contains at least one binder.

[0162] The binder contributes to the film-forming property when the ink coating is formed, and further contributes to the film quality of the ink coating.

[0163] As the binder, a known resin can be used.

[0164] As the binder, an epoxy resin is preferred, a fluorene-based epoxy resin or a bisphenol A-type epoxy resin is more preferred, and a fluorene-based epoxy resin is further preferred.

[0165] The content of the binder (eg, epoxy resin) in the ink according to the first embodiment is preferably 0.3% to 40% by mass, more preferably 10% to 35% by mass, and even more preferably 10% to 30% by mass, relative to the total amount of the ink.

[0166] The binder preferably contains at least one resin having an average refractive index n of 1.50 or more in a wavelength range of 400 nm to 700 nm.

[0167] This makes it easier to achieve an average refractive index n of 1.60 or more for the coating film.

[0168] More preferably, the adhesive 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 a wavelength range of 400 nm to 700 nm.

[0169] This makes it easier to achieve an average refractive index n of 1.60 or more for the coating film.

[0170] The proportion of the epoxy resin A in the adhesive is preferably 50% by mass or more, more preferably 60% by mass or more, and even more preferably 80% by mass or more.

[0171] The epoxy resin A preferably contains a fluorene-based epoxy resin.

[0172] 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.

[0173] When the ink involved in the first embodiment contains an epoxy resin (for example, epoxy resin A), the ink involved in the first embodiment preferably also contains a thiol-based curing agent as a curing agent for the epoxy resin, and more preferably also contains a thiol-based curing agent as a curing agent for the epoxy resin and a tertiary amine as a curing accelerator.

[0174] When the ink according to the first aspect contains a thiol-based curing agent as a curing agent for epoxy resin, the film-forming property when forming an ink coating film (particularly, the film-forming property when heated at a relatively low temperature such as 70° C. or less) is more excellent.

[0175] As a thiol type curing agent, jERCure QX40 manufactured by Mitsubishi Chemical Corporation is mentioned, for example.

[0176] Regarding the thiol-based curing agent, known documents such as JP-A-2019-210325 and JP-A-2016-75845 can be appropriately referred to.

[0177] The content of the thiol curing agent is preferably 0.2 to 20.0% by mass, more preferably 1.0 to 20.0% by mass, further preferably 2.0 to 20.0% by mass, and further preferably 5.0 to 20.0% by mass, relative to the total amount of the ink.

[0178] As for the tertiary amine as a curing accelerator, DMP-30 (2,4,6-tris(dimethylaminomethyl)phenol) manufactured by FUJIFILM Wako Pure Chemical Corporation can be mentioned, for example.

[0179] Regarding the tertiary amine as a curing accelerator, known documents such as JP-A-2015-67832 and JP-A-2021-187910 can be appropriately referred to.

[0180] 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, based on the total amount of the ink.

[0181] <Volatile components>

[0182] The ink according to the first aspect contains at least one volatile component.

[0183] The content of the volatile component is preferably 50% by mass or more, more preferably 55% by mass or more, and even more preferably 60% by mass or more, relative to the total amount of the ink.

[0184] The volatile component preferably contains an organic solvent, and more preferably contains an organic solvent having a boiling point of 180° C. or lower.

[0185] When the volatile component contains an organic solvent having a boiling point of 180° C. or lower, the film-forming property when forming an ink coating film (particularly, the film-forming property when heated at a relatively low temperature such as 70° C. or lower) is more excellent.

[0186] The proportion of the organic solvent having a boiling point of 180° C. or lower in the organic solvent as the volatile component is preferably 50% by mass or more, more preferably 60% by mass or more, and even more preferably 80% by mass or more.

[0187] In the present invention, the "boiling point" refers to the boiling point under atmospheric pressure.

[0188] 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.

[0189] These are all organic solvents having a boiling point of 180° C. or less.

[0190] Examples of organic solvents having a boiling point of 180° C. or less include, in addition to the above examples, ethanol, isopropanol, ethyl acetate, isobutyl acetate, butyl acetate, methyl ethyl ketone, methyl isobutyl ketone, xylene, acetone, ethyl cellosolve, ether, hexane, 1-butanol, methylcyclohexane, ethylcyclohexane, isohexane, butoxyethanol, 1-butoxy-2-propanol, trichloroethylene, tetrachloroethylene, methanol, cellosolve acetate, mineral spirits, tetrahydrofuran, dioxane, and ethyl lactate.

[0191] The ink according to the first aspect may contain an organic solvent having a boiling point exceeding 180°C.

[0192] Examples of the organic solvent having a boiling point exceeding 180° C. include γ-butyrolactone and diethylene glycol diethyl ether.

[0193] <Silane coupling agent>

[0194] The ink of the first aspect may contain at least one silane coupling agent.

[0195] When the ink of the first embodiment contains a silane coupling agent, the adhesion of the formed coating film to the optical component, the hardness of the formed coating film, and the solvent resistance of the formed coating film are further improved.

[0196] As the silane coupling agent, a silane compound containing at least one functional group A selected from an epoxy group, an amino group, a mercapto group, and an isocyanate group is preferred.

[0197] The silane coupling agent contains the functional group A, so that the adhesion with the adhesive is more excellent.

[0198] From the viewpoint of adhesion to optical components, the silane coupling agent containing the functional group A may further contain an alkoxy group (preferably a methoxy group, an ethoxy group, etc.).

[0199] Specific examples of silane coupling agents include, for example,

[0200] 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane,

[0201] 3-Glycidoxypropyltrimethoxysilane,

[0202] 3-Glycidoxypropylmethyldimethoxysilane,

[0203] 3-Glycidoxypropylmethyldiethoxysilane,

[0204] 3-Glycidoxypropyltriethoxysilane,

[0205] 8-Glycidoxyoctyltrimethoxysilane,

[0206] 3-Aminopropyltrimethoxysilane,

[0207] 3-Aminopropyltriethoxysilane,

[0208] Aminoethylaminopropyltrimethoxysilane,

[0209] 3-aminoethylaminopropyltrimethoxysilane,

[0210] 3-isocyanatepropyltriethoxysilane,

[0211] 3-Mercaptopropyltrimethoxysilane, and

[0212] 3-Mercaptopropylmethyldimethoxysilane.

[0213] Specific examples of the silane coupling agent include organosilanes containing a functional group A other than the above-mentioned specific examples.

[0214] As the silane coupling agent, a commercially available product may be used.

[0215] Examples of commercially available products of 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane include KBM-303 manufactured by Shin-Etsu Chemical Co., Ltd. and DOWSIL (registered trademark) Z-6043 Silane manufactured by Dow Corning Toray Industries, Inc.

[0216] Examples of commercially available products of 3-glycidoxypropyltrimethoxysilane include KBM-403 manufactured by Shin-Etsu Chemical Co., Ltd. and DOWSIL (registered trademark) Z-6040 Silane manufactured by Dow Corning Toray Industries, Inc.

[0217] As a commercial item of 3-glycidoxypropylmethyldimethoxysilane, KBM-402 manufactured by Shin-Etsu Chemical Co., Ltd. is mentioned, for example.

[0218] As a commercial item of 3-glycidoxypropylmethyldiethoxysilane, KBE-402 manufactured by Shin-Etsu Chemical Co., Ltd. is mentioned, for example.

[0219] As a commercial product of 3-glycidoxypropyltriethoxysilane, KBE-403 manufactured by Shin-Etsu Chemical Co., Ltd. is mentioned, for example.

[0220] As a commercial product of 8-glycidoxyoctyltrimethoxysilane, KBM-4803 manufactured by Shin-Etsu Chemical Co., Ltd. is mentioned, for example.

[0221] Examples of commercially available organosilanes containing an epoxy group as the functional group A (excluding the above-mentioned specific examples) include X-12-981S manufactured by Shin-Etsu Chemical Co., Ltd. and X-12-984S manufactured by Shin-Etsu Chemical Co., Ltd.

[0222] As a commercial product of 3-aminopropyltrimethoxysilane, KBM-903 manufactured by Shin-Etsu Chemical Co., Ltd. is mentioned, for example.

[0223] Examples of commercially available products of 3-aminopropyltriethoxysilane include KBE-903 manufactured by Shin-Etsu Chemical Co., Ltd. and DOWSIL (registered trademark) Z-6011 Silane manufactured by Dow Corning Toray Industries, Inc.

[0224] As a commercial product of aminoethylaminopropyltrimethoxysilane, DOWSIL (registered trademark) Z-6062 Silane manufactured by Dow Corning Toray Corporation is mentioned, for example.

[0225] As a commercial product of 3-aminoethylaminopropyltrimethoxysilane, DOWSIL (registered trademark) Z-6094 Silane manufactured by Dow Corning Toray Corporation is mentioned, for example.

[0226] Examples of commercially available organosilanes containing an amino group as the functional group A (excluding the above-mentioned specific examples) include X-12-972F manufactured by Shin-Etsu Chemical Co., Ltd.

[0227] As a commercial product of 3-isocyanatepropyltriethoxysilane, KBE-9007 manufactured by Shin-Etsu Chemical Co., Ltd. is mentioned, for example.

[0228] Examples of commercially available organosilanes containing an isocyanate group as the functional group A (excluding the above-mentioned specific examples) include X-12-1159L manufactured by Shin-Etsu Chemical Co., Ltd.

[0229] Examples of commercially available products of 3-mercaptopropyltrimethoxysilane include KBM-803 manufactured by Shin-Etsu Chemical Co., Ltd. and DOWSIL (registered trademark) Z-6062Silane manufactured by Dow Corning Toray Industries, Inc.

[0230] As a commercial product of 3-mercaptopropylmethyldimethoxysilane, KBM-802 manufactured by Shin-Etsu Chemical Co., Ltd. is mentioned, for example.

[0231] Examples of the organosilane containing a mercapto group as the functional group A (excluding the above-mentioned specific examples) include X-12-1154 manufactured by Shin-Etsu Chemical Co., Ltd. and X-12-1156 manufactured by Shin-Etsu Chemical Co., Ltd.

[0232] When the ink of the first embodiment contains a silane coupling agent, the content of the silane coupling agent 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, relative to the total amount of the binder in the ink of the first embodiment.

[0233] When the content of the silane coupling agent is 1% by mass or more, the adhesion of the formed coating film to the optical component, the hardness of the formed coating film, and the solvent resistance of the formed coating film are more excellent.

[0234] When the content of the silane coupling agent is 50% by mass or less, the formed coating film has more excellent light-shielding properties and refractive index.

[0235] <Packing>

[0236] The ink of the first aspect may contain at least one filler.

[0237] When the ink of the first embodiment contains a filler, the gloss of the formed coating film is further suppressed.

[0238] The material of the filler can be inorganic, organic, or an inorganic-organic composite.

[0239] The filler may contain two or more materials.

[0240] 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.

[0241] Examples of the filler include particles having an average primary particle size of 1 μm to 30 μm (preferably 2 μm to 30 μm).

[0242] The shape of the filler may be any shape such as spherical or flake.

[0243] When the filler has a shape other than a spherical shape, the particle size of the filler refers to the equivalent circle diameter of the filler.

[0244] As the filler, commercially available products may be used.

[0245] Commercially available mica as filler includes, for example:

[0246] Mica manufactured by Yamaguchi Mica Co., Ltd. (product name A-11, average primary particle size 3 μm, flake-shaped),

[0247] Mica manufactured by Yamaguchi Mica Co., Ltd. (product name SJ-005, average primary particle size 5 μm, flake-shaped),

[0248] Mica manufactured by Yamaguchi Mica Co., Ltd. (product name TM-10, average primary particle size 11 μm, flake-shaped),

[0249] Mica (product name A-21S, average primary particle size 22 μm, flake-shaped) manufactured by Yamaguchi Mica Co., Ltd., and

[0250] Mica manufactured by Yamag Chimica Co., Ltd. (product name SYA-21R, average primary particle size 27 μm, flake-shaped).

[0251] Commercially available silicone resin particles as fillers include, for example:

[0252] Silicone resin powder manufactured by Micron Technology (Product name: Tosun 120, average primary particle size: 2 μm, spherical shape) manufactured by Micron Materials Co., Ltd.

[0253] Silicone resin powder manufactured by Shin-Etsu Chemical Co., Ltd. (product name KPM-590, average primary particle size 2 μm, spherical),

[0254] Silicone resin powder manufactured by Shin-Etsu Chemical Co., Ltd. (product name X-52-1620, average primary particle size 5 μm, spherical),

[0255] Silicone resin powder manufactured by Micron Technology Co., Ltd. (Product name: Tosun 2000B, average primary particle size: 6 μm, spherical shape), and

[0256] Silicone resin powder manufactured by Micron Technology Co., Ltd. (Product name: Tossil 1110, average primary particle size: 11 μm, spherical shape).

[0257] Commercially available silicone rubber particles as fillers include, for example,

[0258] Silicone rubber powder manufactured by Shin-Etsu Chemical Co., Ltd. (product name KMP-597, average primary particle size 5 μm, spherical),

[0259] Silicone rubber powder manufactured by Shin-Etsu Chemical Co., Ltd. (product name KMP-598, average primary particle size 13 μm, spherical), and

[0260] Silicone rubber powder manufactured by Shin-Etsu Chemical Co., Ltd. (product name KMP-402, average primary particle size 30 μm, spherical).

[0261] Commercially available silicone resin / silicone rubber composite particles as fillers include, for example,

[0262] Silicone resin / silicone rubber composite powder manufactured by Shin-Etsu Chemical Co., Ltd. (product name KMP-605, average primary particle size 2 μm, spherical),

[0263] Silicone resin / silicone rubber composite powder manufactured by Shin-Etsu Chemical Co., Ltd. (product name KMP-600, average primary particle size 5 μm, spherical),

[0264] Silicone resin / silicone rubber composite powder manufactured by Shin-Etsu Chemical Co., Ltd. (product name KMP-601, average primary particle size 12 μm, spherical), and

[0265] Silicone resin / silicone rubber composite powder manufactured by Shin-Etsu Chemical Co., Ltd. (product name KMP-602, average primary particle size 30 μm, spherical shape).

[0266] Examples of commercially available products of urethane resin particles as fillers include urethane resin particles manufactured by Negami Industries, Ltd. (product name: U-600T, average primary particle size: 10 μm, spherical).

[0267] Commercially available products of acrylic resin particles as fillers include, for example,

[0268] Acrylic resin particles manufactured by Negami Industries (product name G-800BK, average primary particle size 6 μm, spherical), and

[0269] Acrylic resin particles manufactured by Negami Industries (product name: G-400BK, average primary particle size: 15 μm, spherical).

[0270] Examples of commercially available products of urethane / acrylic composite resin particles as fillers include urethane / acrylic composite resin particles manufactured by Negami Industries, Ltd. (product name TE-812T, average primary particle size 6 μm, spherical).

[0271] When the ink of the first embodiment contains a filler, the content of the filler relative to the total amount of the binder in the ink of the first embodiment is preferably 1% to 40% by mass, more preferably 2% to 30% by mass, and even more preferably 5% to 20% by mass.

[0272] When the content of the filler is 1% by mass or more, the gloss of the formed coating film is further suppressed.

[0273] When the content of the filler is 40% by mass or less, the color tone of the formed coating film is more excellent (for example, the amount of white spots in the coating film can be reduced).

[0274] <Other ingredients>

[0275] The ink according to the first aspect may contain other components besides the above components.

[0276] Regarding other components that may be contained, the descriptions in the aforementioned Patent Document 1 (Japanese Patent Application Laid-Open No. 57-8264) and the aforementioned Patent Document 2 (Japanese Patent Application Laid-Open No. 2012-149197) can be appropriately referred to.

[0277] 《Ink according to the second aspect》

[0278] The ink according to the second aspect contains at least one of a black pigment, a colored pigment, and a colorless pigment, a binder, and a volatile component.

[0279] The average refractive index n of the black pigment, the colored pigment, and the colorless pigment in the wavelength range of 400 nm to 700 nm is 2.00 or more.

[0280] The average extinction coefficient k of black pigment and colored pigment is 0.10 or more.

[0281] The mass ratio of the total of the black pigment, the colored pigment, and the colorless pigment in the total solid content is 6.5% by mass to 25.8% by mass.

[0282] Here, the total solid content refers to all components except volatile components.

[0283] According to the ink according to the second aspect, a coating film for an optical component that is excellent in light-shielding property, internal surface reflection suppression property, refractive index, and film quality can be formed.

[0284] The light-shielding effect is achieved when the total ratio of the black pigment, the colored pigment and the colorless pigment in the total solid content is 6.5 mass % or more and the average extinction coefficient k of the black pigment and the colored pigment is 0.10 or more.

[0285] The effect of suppressing inner surface reflection is an effect obtained by the average refractive index n being 1.60 or more and the ink containing at least one of a colored pigment and a colorless pigment.

[0286] The refractive index effect is an effect obtained by the average refractive index n of each of the black pigment, the colored pigment, and the colorless pigment being 2.00 or more in the wavelength range of 400 nm to 700 nm.

[0287] The film quality effect is obtained when the total ratio of the black pigment, the color pigment, and the colorless pigment in the total solid content is 25.8% by mass or less.

[0288] Preferred aspects of the ink of the second aspect other than the above-mentioned features are the same as the preferred aspects of the ink of the above-mentioned first aspect.

[0289] 〔Coatings for optical components〕

[0290] The coating film for optical components of the present invention contains a black pigment and at least one of a colored pigment and a colorless pigment.

[0291] The average refractive index n in the wavelength range of 400nm to 700nm is greater than 1.70, the average extinction coefficient k in the wavelength range of 400nm to 700nm is 0.10 to 0.15, and the total ratio of the black pigment, the colored pigment and the colorless pigment in the total volume is 10 volume % to 40 volume %.

[0292] According to the coating film for an optical component of the present invention, the same effects as those of the ink according to the first aspect described above can be obtained.

[0293] Preferred embodiments of the coating film for optical components of the present invention are as described in the section "Ink for forming a coating film for optical components".

[0294] 〔Optical components〕

[0295] The optical component of the present invention comprises:

[0296] Substrates for optical components; and

[0297] The coating film for optical components is provided on a part (for example, the outer peripheral surface) of the substrate for optical components.

[0298] The coating film for optical components 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 400nm to 700nm is greater than 1.70, the average extinction coefficient k in the wavelength range of 400nm to 700nm is 0.10 to 0.15, and the total ratio of the black pigment, the colored pigment and the colorless pigment in the total volume is 10 volume % to 40 volume %.

[0299] According to the optical component of the present invention, the same effects as those of the ink according to the first aspect described above can be obtained.

[0300] A preferred embodiment of the coating film for an optical component in the optical component of the present invention is as described in the section about the ink according to the first embodiment.

[0301] Examples of the optical component substrate include a glass substrate and a plastic substrate.

[0302] The method for measuring the average refractive index n of the optical component substrate in the wavelength range of 400nm to 700nm and the preferred range are the same as the method for measuring the average refractive index n of the optical component coating film in the wavelength range of 400nm to 700nm and the preferred range described in one item of the ink involved in the first embodiment.

[0303] From the viewpoint of further improving the inner surface reflection suppression property of the coating film for an optical component, the absolute value of the difference between the average refractive index n of the substrate for an optical component and the average refractive index n of the coating film for an optical component is preferably 0.2 or less, more preferably 0.1 or less.

[0304] The outer diameter of the optical component substrate is, for example, 1 mm to 300 mm, preferably 3 mm to 220 mm, and more preferably 10 mm to 150 mm.

[0305] The thickness of the optical component substrate is, for example, 0.5 mm to 30 mm, preferably 1 mm to 20 mm, and more preferably 2 mm to 15 mm.

[0306] Examples of the optical component of the present invention include lenses, prisms, and waveguides.

[0307] Examples of the optical component substrate in the optical component of the present invention include a lens substrate, a prism substrate, a waveguide substrate, and the like.

[0308] More specifically, the optical components of the present invention include optical components for broadcasting, optical components for movies, optical components for digital cameras, optical components for industrial cameras, optical components for projectors, optical components for vehicle-mounted cameras, optical components for smartphone-mounted cameras, optical components using prisms (for example, binoculars, periscopes, etc.), optical components using optical waveguides (for example, smart glasses, etc.), and the like.

[0309] Example

[0310] Hereinafter, examples of the present invention will be described, but the present invention is not limited to the following examples.

[0311] [Examples 1 to 29, Comparative Examples 1 to 4]

[0312] <Ink Preparation>

[0313] Inks containing the components shown in Tables 1 to 3 were prepared.

[0314] Specifically, the following components were used as the components.

[0315] (Black pigment)

[0316] · Carbon black…HCF#2650 manufactured by Mitsubishi Chemical Corporation

[0317] Titanium carbide…NP-TIC-2-100 manufactured by EM Japan Co., Ltd.

[0318] (Colored Pigments)

[0319] ·Iron (III) oxide…Iron (III) oxide nanoparticles manufactured by RMML Co., Ltd.

[0320] Silicon carbide…NP-SIC-9-100 manufactured by EM Japan Co., Ltd.

[0321] ·Copper (I) oxide…Copper (I) oxide nanoparticles manufactured by RMML Co., Ltd.

[0322] (Colorless Pigment)

[0323] ·Titanium oxide…TTO-55(B) manufactured by ISHIHARA SANGYO KAISHA, LTD.

[0324] · Diamond…N1083 manufactured by Tokyo Chemical Industry Co., Ltd.

[0325] Zirconia… Zirconeo-Cp manufactured by ITEC Co., Ltd.

[0326] ·ITO…Indium Tin Oxide, E-ITO manufactured by Mitsubishi Materials Electronic Chemicals Co., Ltd.

[0327] (Adhesive)

[0328] ·Fluorene epoxy resin…CG-500 manufactured by Osaka Gas Chemicals Co., Ltd.

[0329] ·Bisphenol A type epoxy resin…jER828 manufactured by Mitsubishi Chemical Corporation

[0330] (Curing agent)

[0331] ·Mercaptan-based curing agent…jER Cure QX40 manufactured by Mitsubishi Chemical Corporation

[0332] Modified amine curing agent…Fujicure 7005 manufactured by T&K TOKA Corporation

[0333] (Curing accelerator)

[0334] Tertiary amine: 2,4,6-tris(dimethylaminomethyl)phenol, DMP-30 manufactured by FUJIFILM Wako Pure Chemical Corporation

[0335] (Dispersant)

[0336] Solsperse 39000 manufactured by The Lubrizol Corporation

[0337] (Organic Solvent)

[0338] ・Propyl acetate…Made by FUJIFILM Wako Pure Chemical Corporation

[0339] ·PGMEA…Propylene glycol monomethyl ether acetate, manufactured by FUJIFILM Wako Pure Chemical Corporation

[0340] PGME…Propylene glycol monomethyl ether, manufactured by Tokyo Chemical Industry Co., Ltd.

[0341] ·Toluene…Made by FUJIFILM Wako Pure Chemical Corporation

[0342] · Cyclohexane…Manufactured by FUJIFILM Wako Pure Chemical Corporation

[0343] ·EGMBE…ethylene glycol monobutyl ether, manufactured by Tokyo Chemical Industry Co., Ltd.

[0344] ·DEGDEE…Diethylene glycol diethyl ether, manufactured by FUJIFILM Wako Pure Chemical Corporation

[0345] ·γ-Butyrolactone…Made by FUJIFILM Wako Pure Chemical Corporation

[0346] 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 shown in Tables 1 to 3.

[0347] Here, the refractive index n and the extinction coefficient k are respectively the average refractive index and the extinction coefficient in the wavelength range of 400 nm to 700 nm.

[0348] In addition, the boiling point (bp) of each organic solvent is the boiling point (° C.) under atmospheric pressure.

[0349] <Film formation>

[0350] The ink was applied to one surface of a glass substrate for evaluation (B-270 manufactured by Schott, thickness 2 mm), and the ink was cured by placing the glass substrate coated with the ink in a thermostatic bath and heating it to obtain a coating film.

[0351] <Calculation of the volume ratio of all pigments in the total volume of the coating>

[0352] Use ink and apply at a coating amount of 0.02g / m 2 A coating film was formed under the conditions of heating and drying at 70°C for 2 hours and a film thickness of 20 μm.

[0353] Based on the total volume of the obtained coating and the density of each pigment, the volume proportion (volume %) of all pigments in the total volume of the coating, the volume proportion (volume %) of the black pigment in the total volume of the coating, and the volume proportion (volume %) of pigments other than the black pigment (i.e., colored pigments and colorless pigments) in the total volume of the coating are calculated respectively.

[0354] The results are shown in Tables 1 to 3.

[0355] <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>

[0356] Use ink and apply at a coating amount of 0.02g / m 2 A coating film was formed under the conditions of heating and drying at 70°C for 2 hours and a film thickness of 20 μm.

[0357] The average refractive index n and the average extinction coefficient k of the obtained coating film in the wavelength range of 400 nm to 700 nm were measured.

[0358] These measurements were performed using a high-speed spectroscopic ellipsometer M-2000 manufactured by JAWOOLLAM JAPAN Inc.

[0359] <Evaluation of color tone of coating film>

[0360] The color tone of the coating film whose average refractive index n and average extinction coefficient k were measured was visually confirmed.

[0361] The results are shown in Tables 1 to 3.

[0362] The color tone of the coating film is particularly preferably jet black.

[0363] <Evaluation of coating film quality (adhesion)>

[0364] Use ink and apply at a coating amount of 0.02g / m 2 A coating film for adhesion evaluation was formed under the conditions of heating and drying at 70° C. for 2 hours and a film thickness of 20 μm.

[0365] The coating film for adhesion evaluation was subjected to a 100-grid test according to ISO 2409 (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 the 100-grid test, 25 1 mm square grids were formed at a cutting interval of 1 mm.

[0366] The results are shown in Tables 1 to 3.

[0367] In the following evaluation criteria, the coating film having the most excellent adhesion was rated as A.

[0368] -Evaluation criteria for adhesion of coating films-

[0369] A: Among 25 grids, 0 grids were peeled.

[0370] B: Among 25 grids, one or two grids were peeled off.

[0371] C: Among 25 grids, 3 or more grids were peeled off.

[0372] D: Film-forming property is insufficient, and the film shape is not formed, and cannot be evaluated.

[0373] <Evaluation of coating film quality (solvent resistance)>

[0374] Use ink and apply at a coating amount of 0.02g / m 2 A coating film for solvent resistance evaluation was formed under the conditions of heating and drying conditions of 70° C. for 2 hours and a film thickness of 20 μm.

[0375] The surface of the coating film for solvent resistance evaluation was rubbed with a cotton swab soaked in isopropyl alcohol, and visual confirmation was made as to whether the color of the coating film adhered to the cotton swab. The solvent resistance of the coating film was evaluated according to the following evaluation criteria.

[0376] In the following evaluation criteria, the coating film having the most excellent solvent resistance was rated as A.

[0377] The results are shown in Tables 1 to 3.

[0378] -Evaluation criteria for solvent resistance of coating films-

[0379] A: Even after 20 reciprocating rubbing operations with a cotton swab, no color of the coating film was observed to adhere to the cotton swab.

[0380] B: Even when the cotton swab was rubbed 10 times, the color of the coating film was not observed on the cotton swab. However, when the rubbing operation was repeated 11 times to 20 times, the color of the coating film was observed on the cotton swab.

[0381] C: The color of the coating film was confirmed to be attached to the cotton swab when the rubbing operation was repeated 1 to 10 times.

[0382] D: Film-forming property is insufficient, and the film shape is not formed, and cannot be evaluated.

[0383] [Table 1]

[0384]

[0385] [Table 2]

[0386]

[0387] [Table 3]

[0388]

[0389] As shown in Tables 1 to 3, the ink of each embodiment contains at least one of a black pigment, a colored pigment and a colorless pigment and a binder. When set as a coating, the average refractive index n of the coating for optical components in the wavelength range of 400nm to 700nm is greater than 1.60, the average extinction coefficient k of the coating is 0.10 to 0.15, and the total ratio of the black pigment, the colored pigment and the colorless pigment in the total volume of the coating is 10 volume % to 40 volume %.

[0390] Since the coating films of each example have an average refractive index n of 1.60 or more and an average extinction coefficient k of 0.15 or less, when used as coating films for high refractive index optical components, they have excellent internal surface reflection suppression properties (i.e., performance of suppressing internal surface reflection in optical components).

[0391] The coatings of the examples have an average extinction coefficient k of 0.10 or more, which means that they have excellent light shielding properties. This allows the coatings for optical components to be formed with a thin film thickness, thereby reducing the variation in film thickness, and as a result, improving the positional accuracy of the optical components when they are assembled into a lens frame.

[0392] Since the total ratio of black pigment, color pigment and colorless pigment in the total volume of the coating film is 10 volume % or more, the coating film of each example has excellent light shielding property (that is, the average extinction coefficient k can be 0.10 or more; refer to Table 1 to Table 3).

[0393] Since the total ratio of the black pigment, the colored pigment and the colorless pigment in the total volume of the coating film is 40 volume % or less, the coating film of each example has excellent film quality (ie, adhesion and solvent resistance) (see Tables 1 to 3).

[0394] The results of each example and comparative example are as follows.

[0395] In Comparative Example 1 in which the total ratio of the black pigment, the colored pigment, and the 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 shielding property was reduced.

[0396] In Comparative Example 2, in which the total volume of the coating film contained more than 40% by volume of the black pigment, the colored pigment, and the colorless pigment, the coating film had insufficient film quality (specifically, insufficient film-forming property and no film-forming shape). This is believed to be due to the relatively insufficient amount of the binder.

[0397] In the coating films of Comparative Examples 3 and 4 using inks containing a black pigment but not containing a color pigment or a colorless pigment, the average extinction coefficient k exceeded 0.15, and the inner surface reflection suppressing property decreased.

[0398] In Examples 1 to 29, in Examples 1 to 21 and 27 to 29 in which the binder contained an epoxy resin having an average refractive index n of 1.60 or more, the average refractive index n of the coating film was increased to 1.70 or more.

[0399] Among Examples 1 and 27, in Example 1 using a thiol-based curing agent as the curing agent for the epoxy resin, the film quality of the coating film under the heating and drying conditions at a low temperature (70° C. or lower) was more excellent.

[0400] Among Examples 1, 28, and 29, in Example 1 in which the volatile component included an organic solvent having a boiling point of 180° C. or less, the film quality of the coating film under the heating and drying condition at a low temperature (70° C. or less) was more excellent.

[0401] [Examples 101 to 104]

[0402] The same operation as in Example 1 (including various evaluations) was performed except that the silane coupling agent and filler in the amounts shown in Table 4 were added to the ink components and the amount of the organic solvent was adjusted to the amount shown in Table 4.

[0403] The results are shown in Table 4.

[0404] As a silane coupling agent, 3-glycidoxypropyltrimethoxysilane (KBM-403 manufactured by Shin-Etsu Chemical Co., Ltd.) was used.

[0405] As the filler, silicone resin powder X-52-1621 (average particle size 5 μm) manufactured by Shin-Etsu Chemical Co., Ltd. was used.

[0406] For comparison, Table 4 also shows the results of Example 1 above.

[0407] <Coating film evaluation 2>

[0408] The coating films obtained in Examples 101 to 104 and Example 1 were subjected to the following coating film evaluation 2.

[0409] The coating film evaluation 2 included the coating film adhesion 2, the coating film solvent resistance 2, the coating film hardness, the coating film glossiness, and the coating film color tone 2 (amount of white spots).

[0410] The results are shown in Table 4.

[0411] (Coating film adhesion 2)

[0412] Use ink, the coating amount is 0.02g / m 2 A coating film for evaluating adhesion was formed on the glass substrate under the conditions of heating and drying at 70° C. for 2 hours and a film thickness of 20 μm.

[0413] The adhesion between the obtained coating film and the glass substrate was measured by the peeling 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. Regarding the adhesion 2 of the coating film, the best grade was 3.

[0414] -Evaluation Criteria-

[0415] 3: After being placed in a high temperature and high humidity (85°C 85% rh) environment for more than one week, it still has obvious adhesion.

[0416] 2: After being placed in a high temperature and high humidity (85°C, 85% rh) environment for less than a week, it still has significant adhesion (except for the case of "3" above).

[0417] 1: If it is not placed in a high temperature and high humidity (85°C 85% rh) environment, it has significant adhesion.

[0418] (Solvent resistance of coating film 2)

[0419] Use ink, the coating amount is 0.02g / m 2 A coating film for evaluating solvent resistance was formed under the conditions of heating and drying at 70° C. for 2 hours and a film thickness of 20 μm.

[0420] The solvent resistance of the coating film for solvent resistance evaluation was evaluated using each solvent of isopropyl alcohol (IPA), acetone, ethyl acetate, and methyl ethyl ketone (MEK).

[0421] Specifically, a 2 mm thick cotton swab soaked in each solvent was rubbed back and forth 10 times on the surface of the coating film under a load of 1 N, and the color of the coating film was visually confirmed to be attached to the cotton swab. The solvent resistance 2 of the coating film was evaluated according to the following evaluation criteria. For the solvent resistance 2 of the coating film, the best level was 3.

[0422] -Evaluation Criteria-

[0423] 3: Ethyl acetate, MEK, acetone and IPA have no color attached to the cotton swab.

[0424] 2: Ethyl acetate and MEK can be seen with color attached to the cotton swab, while IPA and acetone have no color attached to the cotton swab.

[0425] 1: Ethyl acetate, MEK and acetone can be seen with color attached to the cotton swab, but IPA has no color attached to the cotton swab.

[0426] 0: Ethyl acetate, MEK, acetone, and IPA can all be seen with color attached to the cotton swab.

[0427] (Hardness of coating film)

[0428] Use ink, the coating amount is 0.02g / m 2 A coating film for hardness evaluation was formed under the conditions of heating and drying at 70°C for 2 hours and a film thickness of 20 μm.

[0429] A brass pointed part (acute angle 85°) was pressed against the coating film with a load of 4 N and moved at a speed of 70 mm / s to scratch it, and the width of the scratch was measured. The narrower the scratch, the higher the hardness.

[0430] Based on the measurement results, the hardness of the coating film was evaluated according to the following evaluation criteria. Regarding the hardness of the coating film, the best grade was 3.

[0431] -Evaluation Criteria-

[0432] 3: The scratch width is less than 35μm.

[0433] 2: The scratch width is 35 μm or more and less than 40 μm.

[0434] 1: The scratch width is 40 μm or more and less than 45 μm.

[0435] 0: The scratch width is 45 μm or more.

[0436] (Glossiness of coating film)

[0437] Use ink, the coating amount is 0.02g / m 2A coating film for gloss evaluation was formed under the conditions of heating and drying at 70°C for 2 hours and a film thickness of 20 μm.

[0438] The obtained coating film was measured for "60 degree specular gloss Gs (60°)" using a gloss meter IG-410 manufactured by HORIBA in accordance with JIS Z 8741-1997.

[0439] The lower the value, the more the gloss is suppressed.

[0440] (Color tone 2 of coating film (amount of white spots))

[0441] Use ink, the coating amount is 0.02g / m 2 A coating film for evaluation of color tone 2 (amount of white spots) was formed under the conditions of heating and drying at 70° C. for 2 hours and a film thickness of 20 μm.

[0442] 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.

[0443] -Evaluation Criteria-

[0444] 3: No white spots can be seen

[0445] 2: See very few white spots

[0446] 1: See white spots

[0447] 0: White spots are obvious

[0448] [Table 4]

[0449]

[0450] As shown in Table 4, when the ink contains a silane coupling agent and a filler (Examples 101 to 104), similarly to the case where the ink does not contain a silane coupling agent and a filler (Example 1), the average refractive index n of the coating film is 1.60 or more, the average extinction coefficient k of the coating film is 0.10 to 0.15, and the total ratio of all pigments in the total volume of the coating film is 10 volume % to 40 volume %.

[0451] As with the coating film of Example 1, the coating films of Examples 101 to 104 were confirmed to be excellent in light shielding properties, internal surface reflection suppression properties, refractive index, and film quality.

[0452] It was confirmed that the coating films of Examples 101 to 104 were superior to the coating film of Example 1 in terms of adhesion, solvent resistance, and hardness, and that the gloss was further reduced.

Claims

1. An ink for forming a coating film for an optical component, comprising at least one of a black pigment, a colored pigment and a colorless pigment, a binder and a volatile component, In the case of a coating film for optical components, the average refractive index n of the coating film for optical components in the wavelength range of 400nm to 700nm is greater than 1.60, the average extinction coefficient k of the coating film for optical components in the wavelength range of 400nm to 700nm is 0.10 to 0.15, and the volume ratio of the total of the black pigment, the colored pigment and the colorless pigment in the total volume of the coating film for optical components is 10 volume % to 40 volume %.

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

3. The ink for forming a coating film for an optical component according to claim 1, wherein The average refractive index n of the black pigment, the colored pigment, and the colorless pigment in the wavelength range of 400 nm to 700 nm is respectively greater than 2.00, and the average extinction coefficient k of the black pigment and the colored pigment is respectively greater than 0.

10.

4. An ink for forming a coating film for an optical component, comprising at least one of a black pigment, a colored pigment and a colorless pigment, a binder and a volatile component, The average refractive index n of the black pigment, the colored pigment, and the colorless pigment in the wavelength range of 400 nm to 700 nm is respectively greater than 2.00, The average extinction coefficient k of the black pigment and the colored pigment is respectively greater than 0.10, The mass ratio of the total of the black pigment, the colored pigment, and the colorless pigment in the total solid content is 6.5 mass % to 25.8 mass %.

5. The ink for forming a coating film for an optical component according to claim 1 or 4, wherein The black pigment comprises at least one selected from the group consisting of carbon black and titanium carbide, The colored 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, zirconium oxide, and indium tin oxide.

6. The ink for forming a coating film for an optical component according to claim 1 or 4, wherein The median particle size of the pigment is 100 nm or less.

7. The ink for forming a coating film for an optical component according to claim 1 or 4, wherein The adhesive includes an epoxy resin having an average refractive index n of 1.60 or more in a wavelength range of 400 nm to 700 nm.

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

9. The ink for forming a coating film for an optical component according to claim 7, wherein The epoxy resin includes a heat-curing epoxy resin.

10. The ink for forming a coating film for an optical component according to claim 9, wherein It also contains a thiol curing agent as a curing agent for epoxy resin and a tertiary amine as a curing accelerator.

11. The ink for forming a coating film for an optical component according to claim 1 or 4, wherein The content of the volatile component is 50% by mass or more based on the total amount of the ink for forming a coating film for an optical component.

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

13. The ink for forming a coating film for an optical component according to claim 1 or 4, wherein: 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.

14. The ink for forming a coating film for an optical component according to claim 1 or 4, wherein It further contains a silane coupling agent.

15. The ink for forming a coating film for an optical component according to claim 1 or 4, wherein It further contains a filler.

16. An optical component comprising: Substrates for optical components; and The coating film for optical components is provided on a part of the substrate for optical components. The coating film for optical components contains a black pigment and at least one of a colored pigment and a colorless pigment, an average refractive index n in the wavelength range of 400nm to 700nm is greater than 1.70, an average extinction coefficient k in the wavelength range of 400nm to 700nm is 0.10 to 0.15, and the total ratio of the black pigment, the colored pigment and the colorless pigment in the total volume is 10 volume % to 40 volume %.

17. The optical component according to claim 16, wherein: The optical component is an optical component for broadcasting, an optical component for cinema, an optical component for digital cameras, an optical component for industrial cameras, an optical component for projectors, an optical component for vehicle-mounted cameras, an optical component for smartphone-mounted cameras, an optical component using a prism, or an optical component using an optical waveguide.

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