Dispersion liquid, curable composition, cured product of same, and optical lens

Abstract

Provided are: a dispersion liquid which contains a polymerizable compound (a1), a black colorant (b), and a dispersant (c), wherein the average particle diameter (D50) of the colorant (b) is in the range of 150-500 nm; and a curable composition which can be formed by an inkjet method. The present invention has excellent curability and storage stability, and provides a cured product that has excellent light transmissivity (concealing performance) in the visible region, low reflectivity, adhesion to a substrate, and moisture resistance.

Description

Dispersion, curable composition, cured product thereof, and optical lens

[0001] The present invention relates to a dispersion, a curable composition, a cured product of the curable composition, an optical lens containing the cured product, and a lens module using the cured product.

[0002] Image sensors such as CMOS sensors are generally used in camera modules for mobile phones and digital cameras, as well as in automotive image sensors. In recent years, their applications have expanded to various fields, and further miniaturization and higher resolution are expected. Such image sensors are equipped with an optical lens unit, and the optical lens has an aperture for adjusting the amount of light. Patent Document 1 describes such an optical lens, which is composed of a lens with an integrated aperture. The lens is constructed by depositing metal onto the surface of a transparent substrate made of glass or resin, forming an aperture with the metal deposition film, and then laminating a lens member made of resin on top of it. The aperture is provided inside the lens body, which is composed of the transparent substrate and the lens member. Furthermore, in recent years, in response to the trend towards miniaturization and higher resolution of elements, Patent Document 2 proposes an ink for forming light-shielding materials that can be formed by drawing the aperture function of an optical lens using an inkjet method. However, in order to accommodate the miniaturization and higher resolution of optical lenses, in addition to the light-shielding properties necessary for adjusting the amount of light, it was necessary to reduce phenomena such as flare and ghosting, which are factors that degrade image quality due to diffuse reflection of light.

[0003] Japanese Patent Publication No. 2009-301061 Japanese Patent Publication No. 2012-208391

[0004] As mentioned above, in order to respond to the trend towards miniaturization and higher resolution of various lens modules, there is a need for light-shielding materials that can precisely form the aperture function of optical lenses using an inkjet method, and that can achieve both excellent light shielding and reduction of factors that degrade image quality. Specifically, there is a need for light-shielding materials that sufficiently shield incident light in an optical lens while simultaneously reducing reflected light caused by the light-shielding layer.

[0005] As a result of diligent research, the present inventors have found that a dispersion liquid in which a black colorant having a specific average particle size, a polymerizable compound, and a dispersant are selected as constituent components exhibits excellent dispersibility and storage stability; that a curable composition prepared from such a dispersion liquid exhibits excellent curability, enabling the formation of molded products by inkjet printing; and that the resulting cured product exhibits excellent physical properties such as low light transmittance (opacity) in the visible region, low reflectivity, heat resistance, light resistance, and moisture resistance, making it useful as a black curable material for optical elements having lens modules such as optical lenses. The object of the present invention is to provide a curable composition that exhibits excellent curability and storage stability, as well as excellent low light transmittance (opacity) in the visible region, low reflectivity, moisture resistance, and adhesion to a substrate, and that can be formed by inkjet printing.

[0006] The present invention has the following embodiments: [1] A dispersion containing a polymerizable compound (a1), a black coloring agent (b), and a dispersant (c), wherein the average particle size (D50) of the black coloring agent (b) is in the range of 150 to 500 nm. [2] The dispersion according to [1], wherein the polymerizable compound (a1) contains a monofunctional (meth)acrylate. [3] The dispersion according to [2], wherein the monofunctional (meth)acrylate is a monofunctional (meth)acrylate having a cyclic skeleton. [4] The dispersion according to [1], wherein the black coloring agent (b) contains a black pigment. [5] A curable composition containing the dispersion according to [1] and a polymerizable compound (a2). [6] The curable composition according to [5], wherein the polymerizable compound (a2) contains a (meth)acrylate having a hydroxyl group. [7] The curable composition according to [5] or [6], further comprising a photopolymerization initiator (d). [8] The curable composition of [7] wherein the photopolymerization initiator (d) comprises an acylphosphine-based photopolymerization initiator. [9] The curable composition of any one of [5] to [8] wherein the content of the black coloring agent (b) is 3 to 40% by mass relative to the total mass of the curable composition.

[10] The curable composition of any one of [5] to [9] which is an active energy ray curable composition.

[11] The curable composition of any one of [5] to

[10] which does not contain a solvent.

[12] The curable composition of the [5] to

[11] which is a light-shielding composition for optical lenses.

[13] A cured product of any one of the curable compositions of [5] to

[12] .

[14] A method for producing a cured product, comprising the step of curing any one of the curable compositions of [5] to

[12] by irradiating it with active energy rays.

[15] The method for producing

[14] wherein the curable composition is formed by an inkjet method.

[16] An optical lens with a light-shielding material, using a cured product of any of the curable compositions of [5] to

[12] .

[17] The optical lens with a light-shielding material according to

[16] , using any of the following materials as a substrate: cyclic olefin copolymer (COC), cycloolefin polymer (COP), or polycarbonate resin (PC).

[18] A camera module equipped with the optical lens with a light-shielding material according to

[17] .

[0007] According to the present invention, it is possible to provide a curable composition that allows the formation of a cured product by an inkjet method that is excellent in curability and storage stability, as well as excellent in low light transmittance (opacity), low reflectivity, moisture resistance, and adhesion to a substrate in the visible region.

[0008] This figure schematically shows the coating position as one embodiment of an optical lens in which a light-shielding cured product of the curable composition of the present invention is coated at a desired location. This figure schematically shows one embodiment in which the curable composition of the present invention is coated by an inkjet method and cured with ultraviolet light. It shows a configuration in which the ink ejection head and ultraviolet lamp are arranged side by side. This figure schematically shows one embodiment in which the curable composition of the present invention is coated by an inkjet method and cured with ultraviolet light. It shows a configuration in which the ejection head and ultraviolet lamp are arranged vertically, with the head on the upper level and the ultraviolet lamp on the lower level. This figure schematically shows a configuration in which the back surface reflectance of the light-shielding layer and the substrate is measured using an integrating sphere on a lens substrate coated with the light-shielding layer of the present invention. This shows a graph of the results of measuring the wavelength dispersion of the back surface reflectance when the curable composition 1 described in Example 1 is coated on a PC substrate and a light-shielding layer of 5 μm thickness is provided. This shows a graph plotting the back surface reflectance at a wavelength of 550 nm when the back surface reflectance of curable compositions 1 to 5 described in each example and comparative example is coated on a PC substrate and a light-shielding layer of 5 μm thickness is provided.

[0009] The present invention relates to a dispersion (hereinafter simply referred to as "the dispersion of the present invention") containing a polymerizable compound (a1), a black coloring agent (b), and a dispersant (c), wherein the average particle size (D50) of the coloring agent (b) is in the range of 150 to 500 nm. The present invention also relates to a curable composition (hereinafter simply referred to as "the curable composition of the present invention") containing the above-described dispersion and a polymerizable compound (a2). In this specification, a composition containing the dispersion of the present invention, a polymerizable compound (a2), and various components described later is referred to as a curable composition. In this specification, "(meth)acrylate" is a general term for acrylate, methacrylate, and both thereof. "(meth)acrylic" is a general term for acrylic, methacrylic, and both thereof. "(meth)acryloyloxy group" is a general term for acryloyloxy group, methacryloyloxy group, and both thereof.

[0010] The dispersion of the present invention exhibits excellent dispersibility of the black coloring agent (b) and excellent storage stability. The curable composition of the present invention contains the dispersion of the present invention as a component and exhibits excellent curability and storage stability. Furthermore, from the curable composition of the present invention, a cured product with excellent low light transmittance (opacity), low reflectivity, moisture resistance, and adhesion to the substrate can be formed by inkjet printing. First, the composition of the dispersion of the present invention will be described.

[0011] The polymerizable compound (a1) constituting the dispersion of the present invention preferably contains a monofunctional (meth)acrylate. The inclusion of a monofunctional (meth)acrylate makes it easier to reduce the viscosity of the dispersion of the present invention, and of the curable composition of the present invention, which contains the dispersion of the present invention as a component, as described later. The polymerizable compound (a1) constituting the dispersion of the present invention preferably contains a monofunctional (meth)acrylate having a cyclic skeleton. In the dispersion of the present invention, the monofunctional (meth)acrylate can be cyclohexyl (meth)acrylate, 4-t-butylcyclohexyl (meth)acrylate, tricyclodecanedimethanol mono(meth)acrylate, adamantyl (meth)acrylate, cyclohexanedimethanol mono(meth)acrylate, trimethylcyclohexyl (meth)acrylate, isobornyl (meth)acrylate, t-butylcyclohexyl (meth)acrylate, dicyclopentanyl (meth)acrylate, dicyclo Examples include monofunctional (meth)acrylates having an alicyclic skeleton such as pentenyloxyethyl (meth)acrylate, and monofunctional (meth)acrylates having aromatic rings such as 2-phenoxyethyl (meth)acrylate, benzyl (meth)acrylate, m-phenoxybenzyl (meth)acrylate, 1-naphthalenemethyl (meth)acrylate, methylphenoxyethyl (meth)acrylate, phenoxydiethylene glycol (meth)acrylate, and phenoxy(polyethylene glycol) (meth)acrylate. One type of monofunctional (meth)acrylate having an alicyclic skeleton or one type of monofunctional (meth)acrylate having an aromatic ring may be used alone, or two or more types may be used in combination. The viscosity of the polymerizable compound (a1) at 25°C is preferably 30 mPa·s or less, more preferably in the range of 1 to 20 mPa·s, even more preferably in the range of 2 to 10 mPa·s, and even more preferably in the range of 2 to 6 mPa·s. When the viscosity of the polymerizable compound (a1) at 25°C is within the aforementioned range, the dispersion of the present invention exhibits excellent dispersibility, low viscosity, and ease of handling. Including a monofunctional (meth)acrylate having an alicyclic skeleton results in a low viscosity and excellent dispersibility of the dispersion of the present invention, which is particularly preferable.When a monofunctional (meth)acrylate having an aromatic ring is included, dispersibility tends to be improved when the colorant (b) is an organic black pigment. Since organic black pigments generally have an aromatic ring structure, it is presumed that using a monofunctional (meth)acrylate having an aromatic ring as the polymerizable compound (a1) increases the affinity between the two and improves solubility, making it easier to reduce the viscosity of the resulting dispersion. The polymerizable compound (a1) may also preferably contain the monofunctional (meth)acrylate having an alicyclic skeleton as described above, to the extent that it can maintain the viscosity of the dispersion of the present invention and the dispersibility of the colorant (b), and may contain a monofunctional (meth)acrylate having an aromatic ring and a compound having two or more (meth)acrylate groups that can constitute the curable composition of the present invention, as described later. In the total polymerizable compound in the dispersion of the present invention, it is preferable that the monofunctional (meth)acrylate having an alicyclic skeleton is contained in an amount of 10% by mass or more, and more preferably 15% by mass or more, to achieve low viscosity and good solubility. The content of polymerizable compound (a1) in the dispersion of the present invention is preferably in the range of 40 to 99% by mass, more preferably in the range of 50 to 90% by mass, and even more preferably in the range of 60 to 85% by mass.

[0012] The black coloring agent (b) constituting the dispersion of the present invention is not particularly limited, and known black pigments can be used, specifically organic black pigments and inorganic black pigments. The black coloring agent (b) may contain one or both of the organic black pigment and the inorganic black pigment. Furthermore, the black coloring agent (b) may be either an unacidified pigment or an acidified pigment. Examples of black organic pigments include dioxazine-based pigments, indanthron-based pigments, diketopyrrolopyrrole-based pigments, isoindoline-based pigments, bisbenzofuranone-based pigments (lactone-based pigments), and perylene-based pigments. Among these, it is preferable that the black coloring agent (b) constituting the dispersion of the present invention contains a bisbenzofuranone-based pigment. The bisbenzofuranone-based pigment may have a structure represented by the following general formulas (I) to (IV), or its isomers or tautomers. For example, general formulas (I) to (III) are cis-trans isomers, and there may be two or more of these structures.

[0013]

[0014] In the formula, R １ and R ２ each independently represents a hydrogen atom or an alkyl group having 1 to 10 carbon atoms. R ３ and R ４ each independently represents R １０ , OR １１ , SR １１ , COR １１ , CONR １１ R １２ , NR １１ COR １２ , OCOR １１ , COOR １１ , SCOR １１ , OCSR １１ , COSR １１ , CSOR １１ , CN, a halogen atom or a hydroxyl group. Here, R １０ represents an alkyl group having 1 to 20 carbon atoms, an aryl group having 6 to 30 carbon atoms, an aralkyl group having 7 to 30 carbon atoms or a heterocyclic group having 2 to 20 carbon atoms, R １１ and R １２Each of the following independently represents a hydrogen atom, an alkyl group having 1 to 20 carbon atoms, an aryl group having 6 to 30 carbon atoms, an aralkyl group having 7 to 30 carbon atoms, or a heterocyclic group having 2 to 20 carbon atoms. Each of the following independently represents an integer from 0 to 4. Bisbenzofuranone pigments having a structure represented by any of the above general formulas (I) to (IV) are publicly known and can be obtained, for example, by the method described in Japanese Patent Publication No. 2012-515233 or by the method described in Example 12b of International Publication No. 2000 / 024736. Commercially available bisbenzofuranone pigments can also be used, for example, "Irgaphor® Black S 0100CF" (trade name) manufactured by BASF. Bisbenzofuranone pigments have higher light transmittance in the 310 nm to 370 nm region compared to carbon black. Therefore, by using a black coloring agent (b) containing a bisbenzofuranone pigment, the curability by active energy rays such as ultraviolet light is significantly improved. Examples of dioxazine pigments include Violet 23, Violet 37, and Blue 80. Examples of indanthron pigments include Blue 60 and Blue 64. Examples of diketopyrrolopyrrole pigments include Red 254, Red 255, Red 264, Orange 71, Orange 73, and Orange 81. Examples of isoindoline pigments include Yellow 139, Yellow 185, Orange 66, Orange 69, and Red 260. Examples of perylene-based pigments include Spectrasense Black EH8082, Spectrasense Black K0088, Paliogen Black S0084, and Paliogen Black L0086. An example of a black inorganic pigment is carbon black. However, carbon black is sometimes classified as a carbon-based pigment. The dispersion of the present invention may further contain other colorants along with the black colorant (b), to the extent that they do not impede the effects of the present invention. Examples of such other colorants include general organic pigments, inorganic pigments, dyes, etc.Examples of organic pigments include azo pigments, phthalocyanine pigments such as copper phthalocyanine, anthraquinone pigments, quinacridone pigments, perinone pigments, thioindigo pigments, isoindolinone pigments, quinophthalone pigments, surene pigments, and metal complex pigments. Examples of inorganic pigments include titanium dioxide, zinc oxide, zinc sulfide, lead white, calcium carbonate, precipitated barium sulfate, white carbon, alumina white, kaolin gray, talc, bentonite, black iron oxide, cadmium red, red iron oxide, molybdenum red, molybdate orange, chromium vermilion, lead yellow, cadmium yellow, yellow iron oxide, titanium yellow, chromium oxide, viridian, titanium cobalt green, cobalt green, cobalt chromium green, Victoria green, ultramarine, Prussian blue, cobalt blue, cerulean blue, cobalt silica blue, cobalt zinc silica blue, manganese violet, cobalt violet, and silica (silicon oxide). Examples of dyes include azo dyes, anthraquinone dyes, condensed polycyclic aromatic carbonyl dyes, indigoid dyes, carbonium dyes, phthalocyanine dyes, methine dyes, and polymethine dyes.

[0015] Other black colorants include, for example, mixed organic pigments obtained by mixing two or more pigments having colors such as red, blue, green, purple, yellow, magenta, and cyan to create a pseudo-black color; fine particles of metals such as graphite, titanium, copper, iron, manganese, cobalt, chromium, nickel, zinc, calcium, and silver; and black inorganic pigments such as oxides, composite oxides, sulfides, nitrides, and oxynitrides of the above metals. As other colorants, phthalocyanine-based pigments are preferred, and copper phthalocyanine-based pigments are more preferred, from the viewpoint of further improving the low light transmittance (opacity), low reflectivity, heat resistance, and moisture resistance in the visible light region of the cured product of the curable composition of the present invention, which will be described later. An example of a copper phthalocyanine-based pigment is "FASTOGEN BLUE AE8" (product name; equivalent to pigment PB15:6) manufactured by Toyo Ink Co., Ltd.

[0016] The average particle size (D50) of the black coloring agent (b) constituting the dispersion of the present invention is 150 to 500 nm, more preferably 160 to 400 nm, and more preferably 180 to 350 nm. When the average particle size (D50) of the black coloring agent (b) is in the range of 150 to 500 nm, the dispersion of the present invention exhibits excellent dispersibility and storage stability. Furthermore, the curable composition of the present invention, described later, containing the dispersion of the present invention becomes easier to handle, reducing the likelihood of nozzle clogging when applying the inkjet method. In addition, the light transmittance of the cured product of the curable composition of the present invention can be sufficiently low, maintaining opacity, and furthermore, the reflection of light incident on the cured product can be sufficiently suppressed. If the average particle size (D50) of the black coloring agent (b) is smaller than 150 nm, the reflected light from the cured product in the visible light region of the curable composition of the present invention increases, causing image quality degradation such as flare and ghosting when used in optical lenses. If the average particle size (D50) of the black colorant (b) is greater than 500 nm, the suitability for inkjet printing deteriorates significantly, such as an increase in viscosity of the curable composition of the present invention and clogging of inkjet printing nozzles. The average particle size (D50) is the volume-based cumulative 50% diameter and can be determined by dynamic light scattering or laser diffraction / scattering. In this example, the measurement was performed using a dynamic light scattering apparatus. The content of the black colorant (b) in the total dispersion of the present invention is in the range of 1 to 50% by mass, preferably in the range of 5 to 45% by mass, more preferably in the range of 10 to 40% by mass, and even more preferably in the range of 15 to 35% by mass. When the content of the black colorant (b) is within the above range, the dispersibility of the black colorant (b) in the dispersion of the present invention can be well maintained. Furthermore, the curability of the curable composition of the present invention, the light resistance of the cured product of the curable composition of the present invention, and the low light transmittance (opacity) and low reflectivity in the visible region can be improved.

[0017] The dispersant (c) is used in the dispersion of the present invention to further enhance the dispersion stability of the black colorant (b) in the polymerizable compound (a1). A polymeric dispersant (c) is preferred, which has both a pigment affinity group that chemically bonds to or adsorbs to the pigment surface and a polymer chain or group that is solvent-friendly. The polymeric dispersant improves the wettability of the pigment to the dispersion medium, promoting deaggregation of the pigment, stabilizing the particle size and viscosity of the pigment through its steric hindrance and electrostatic repulsion effect, and further improving the viscosity reduction and storage stability of the dispersion of the present invention or the curable composition of the present invention described later. Examples of polymeric dispersants include polyester-based, acrylic-based, polyurethane-based, polyallylamine-based, carbodiimide-based, and polyamide-based dispersants. Commercially available products can be used as the dispersant (c), for example, Ajisper (Ajisper is a registered trademark) PB821, PB822, PB824 from Ajinomoto Fine Techno Co., Ltd.; Solsperse (Solsperse is a registered trademark) 24000GR, 32000, 33000, 39000, S86000 from Lubrizol; Disparon DA-703-50 from Kusumoto Chemical Co., Ltd.; EFKA (EFKA is a registered trademark) PX4701, PX4703 from BASF; BYK2013, BYK9151 from BYK, etc. The amount of dispersant (c) used is preferably in the range of 10 to 100% by mass relative to the colorant (b), and more preferably in the range of 15 to 60% by mass from the viewpoint of superior inkjet ejection stability and dispersibility of the colorant (b) in the curable composition of the present invention described later. Furthermore, synergists may be further included from the viewpoint of enhancing the effect of polymer dispersants that stabilize phthalocyanine blue and green, organic violet pigments, etc. A synergist is a pigment derivative in which polar groups such as alkylamino groups, carboxyl groups, sulfonic acid groups, and phthalimide groups are introduced into the pigment skeleton. It can adsorb to the pigment surface through π-π interactions and hydrophobic interactions, modifying the pigment surface to be acidic or basic, and increasing the electrostatic repulsion between pigment particles, thereby improving dispersion stability. In addition, the electrostatic adsorption force with the solvent-philic portion of the dispersant is also increased, so the dispersant can be strongly adsorbed to the pigment surface via the synergist, further improving dispersion stability.Such synergists can be commercially available products, such as BYK's BYK-SYNERGIST 2100 and Lubrizol's Solsperse (Solsperse is a registered trademark) 5000 and 5000S Synergist.

[0018] The dispersion of the present invention may further contain surfactants from the viewpoint of improving handling ease, dispersibility of the black coloring agent (b), and discharge stability and wettability to the substrate of the curable composition of the present invention, which will be described later. Examples of surfactants include anionic surfactants such as dialkyl sulfosuccinates, alkylnaphthalene sulfonates, and fatty acid salts; nonionic surfactants such as polyoxyethylene alkyl ethers, polyoxyethylene alkyl allyl ethers, acetylene glycols, and polyoxyethylene / polyoxypropylene block copolymers; cationic surfactants such as alkylamine salts and quaternary ammonium salts; silicone-based surfactants having silicone chains, polymer chains such as silicone chains and poly(meth)acrylate chains, and silicone-based surfactants having polyether chains as side chains or terminals and a polysiloxane structure in the main chain; and preferably hydrophobic organic fluoro compounds such as fluorine-based surfactants having perfluoroalkyl chains, oily fluorine-based compounds (e.g., fluorine oil), and solid fluorine compound resins (e.g., tetrafluoroethylene resin). These can be obtained as commercially available products such as the "Megafac®" series from DIC Corporation, the "Futergent®" series from Neos Corporation, the "BYK®" series from BYK Corporation, the "TEGO® Rad" series from Evonik Corporation, the "DISPARLON® OX" series from Kusumoto Chemical Co., Ltd., and "Polyflow No. 7," "Floren AC-300," and "Floren AC-303" from Kyoeisha Chemical Co., Ltd. When the dispersion of the present invention contains a surfactant, the amount is preferably 0.05 to 1% by mass, and more preferably 0.1 to 0.8% by mass, relative to the total dispersion of the present invention.

[0019] The dispersion of the present invention preferably does not contain a solvent. In this specification, a solvent means a compound that dissolves the polymerizable compound (a1), the dispersant (c), and the polymerizable compound (a2) and photopolymerization initiator (d) described later, and does not react with these components. Such solvents include ethers such as 3-methoxy-1-butanol, 3-methoxy-3-methylbutanol, tetrahydrofuran, tetrahydropyran, 1,4-dioxane, anisole, and phenethole; and esters such as methyl lactate, ethyl lactate, butyl lactate, methyl 2-hydroxyisobutanoate, ethyl acetate, butyl acetate, pentyl formate, isopentyl acetate, butyl propionate, isopropyl butyrate, ethyl butyrate, butyl butyrate, methyl pyruvate, methyl acetoacetate, and γ-butyrolactone. Ether esters such as ethyl methoxyacetate, butyl methoxyacetate, methyl ethoxyacetate, ethyl ethoxyacetate, methyl 3-methoxypropionate, ethyl 3-methoxypropionate, methyl 3-ethoxypropionate, ethyl 3-ethoxypropionate, methyl 2-methoxypropionate, ethyl 2-ethoxypropionate, ethyl 2-ethoxypropionate, ethyl 2-ethoxypropionate, ethyl 3-methoxybutyl acetate, methyl-3-methoxybutyl acetate; glycol ethers such as ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monopropyl ether, ethylene glycol monobutyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, propylene glycol monopropyl ether, propylene glycol monobutyl ether, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, diethylene glycol methyl ethyl ether, diethylene glycol dipropyl ether, diethylene glycol dibutyl ether;Examples include glycol ether esters such as propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate, ethylene glycol monomethyl ether acetate, ethylene glycol monoethyl ether acetate, diethylene glycol monoethyl ether acetate, diethylene glycol monobutyl ether acetate, and dipropylene glycol methyl ether acetate; alcohols such as methanol, ethanol, propanol, butanol, hexanol, cyclohexanol, ethylene glycol, and propylene glycol; ketones such as acetone, 2-butanone, 2-heptanone, 4-methyl-2-pentanone, cyclopentanone, and cyclohexanone; amides such as N,N-dimethylformamide, N,N-dimethylacetamide, and N-methylpyrrolidone; aliphatic hydrocarbons such as hexane and octane; aromatic hydrocarbons such as benzene, toluene, and xylene; and so on. Furthermore, in this specification, "solvent-free" means that the solvent content in the dispersion of the present invention is 1% by mass or less. The solvent content is preferably 0.5% by mass or less, and more preferably 0.1% by mass or less. The dispersion of the present invention can effectively disperse the black coloring agent (b) even without containing a solvent, and exhibits excellent storage stability. Therefore, the manufacturing process of the dispersion of the present invention can be simplified, and safety during handling can be improved. Furthermore, the curable composition of the present invention, described later, can be coated by an inkjet method, and annealing treatment during curing is unnecessary.

[0020] The dispersion of the present invention can be produced by supplying the polymerizable compound (a1), black coloring agent (b), and dispersant (c) using a conventional disperser such as a bead mill or stirrer, stirring and mixing to disperse the black coloring agent (b). When using a bead mill, glass beads or zirconia beads can be used as beads. In addition to a bead mill, various known and conventional dispersers can be used, such as an ultrasonic homogenizer, high-pressure homogenizer, paint shaker, ball mill, roll mill, sand mill, sand grinder, Dyno mill, Dispermat, SC mill, nanomizer, etc.

[0021] Next, the composition of the curable composition of the present invention will be described. The curable composition of the present invention contains the dispersion of the present invention described above and a polymerizable compound (a2). The curable composition of the present invention preferably contains a (meth)acrylate having a hydroxyl group as the polymerizable compound (a2). Examples of (meth)acrylates having a hydroxyl group include 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, 2-ethylhexyldiglycol (meth)acrylate, diethylene glycol mono(meth)acrylate, 2-hydroxy-3-phenoxypropyl (meth)acrylate, 1,4-cyclohexanedimethanol monoacrylate, 1-(acryloyloxy)-3-(methacryloyloxy)-2-propanol, and the like. One type of these (meth)acrylates having a hydroxyl group may be used alone, or two or more types may be used in combination. In particular, 2-hydroxypropyl (meth)acrylate and 4-hydroxybutyl (meth)acrylate are preferred, and 4-hydroxybutyl acrylate is more preferred, from the viewpoint of being general-purpose, relatively inexpensive to obtain, and having good curability, inkjet ejectability, and excellent physical properties such as moisture resistance and heat resistance of the cured product after curing. When the polymerizable compound (a2) contains a (meth)acrylate having a hydroxyl group, the moisture resistance, heat resistance, and adhesion to the substrate of the cured product formed from the curable composition of the present invention are improved.

[0022] The content of the polymerizable compound (a2), which is a (meth)acrylate having a hydroxyl group, is preferably in the range of 5 to 50% by mass, more preferably in the range of 8 to 40% by mass, and even more preferably in the range of 10 to 35% by mass, relative to the total mass of the curable composition of the present invention. When the curable composition of the present invention contains a (meth)acrylate having a hydroxyl group in this range, the curability is improved, and the performance of the cured product after curing, such as moisture resistance, heat resistance, and adhesion to the substrate, is improved.

[0023] The curable composition of the present invention preferably contains a compound having two or more (meth)acrylate groups as the polymerizable compound (a2). Examples of compounds having two or more (meth)acrylate groups include ethylene glycol di(meth)acrylate, 1,4-butanediol di(meth)acrylate, neopentyl glycol di(meth)acrylate, 3-methyl-1,5-pentanediol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, 1,9-nonanediol di(meth)acrylate, 2-methyl-1,8-octanediol di(meth)acrylate, and 2-butyl-2-ethyl-1,3-propanediol di(meth)acrylate. Glycol di(meth)acrylates such as acrylate, tricyclodecanedimethanol di(meth)acrylate, ethoxylated (2) neopentyl glycol di(meth)acrylate [compound obtained by di(meth)acrylateing a 2-mol adduct of neopentyl glycol ethylene oxide], propoxylated (2) neopentyl glycol di(meth)acrylate [compound obtained by di(meth)acrylateing a 2-mol adduct of neopentyl glycol propylene oxide], and hydroxypivalic acid neopentyl glycol di(meth)acrylate;

[0024] Diethylene glycol di(meth)acrylate, triethylene glycol di(meth)acrylate, tetraethylene glycol di(meth)acrylate, polyethylene glycol di(meth)acrylate, dipropylene glycol di(meth)acrylate, tripropylene glycol di(meth)acrylate, tetrapropylene glycol di(meth)acrylate, polypropylene glycol di(meth)acrylate, polytetramethylene glycol di(meth)acrylate, alkylene glycol di(meth)acrylate such as bis(4-acryloxypolyethoxyphenyl)propane; di(meth)acrylate of tris(2-hydroxyethyl) isocyanurate; dimethylol tricyclodecane di(meth)acrylate, neopentyl glycol di(meth)acrylate modified from caprolactone hydroxypivalate; Bisphenol A di(meth)acrylate, propylene oxide-modified bisphenol A type di(meth)acrylate, ethylene oxide-modified bisphenol A type di(meth)acrylate, bisphenol F di(meth)acrylate, propylene oxide-modified bisphenol F type di(meth)acrylate, ethylene oxide-modified bisphenol F type di(meth)acrylate; pentaerythritol tri(meth)acrylate, trimethylolpropane tri(meth)acrylate, trimethylolpropane ethylene oxide-modified tri(meth)acrylate, trimethylolpropane propylene oxide-modified tri(meth)acrylate, tetramethylolmethane tri(meth)acrylate, modified glycerin tri(meth)acrylate, glycerin propylene oxide adduct tri(meth)acrylate, glycerin ethylene oxide adduct tri(meth)acrylate, and other trifunctional (meth)acrylates; Examples include tetrafunctional (meth)acrylates such as pentaerythritol tetra(meth)acrylate, dipentaerythritol tetra(meth)acrylate, ditrimethylolpropane tetra(meth)acrylate, and tetramethylolmethane tetra(meth)acrylate; and hexafunctional (meth)acrylates such as dipentaerythritol hexa(meth)acrylate and caprolactone-modified dipentaerythritol hexa(meth)acrylate.

[0025] Furthermore, urethane (meth)acrylate and amino (meth)acrylate can also be used as compounds having two or more (meth)acrylate groups. Urethane (meth)acrylate and amino (meth)acrylate may be monomers, oligomers, or polymers. In this specification, "monomer" means a compound with a molecular weight (or weight-average molecular weight if a molecular weight distribution exists) of 1000 or less. The molecular weight (or weight-average molecular weight if a molecular weight distribution exists) of monomers is 50 to 1000. "Oligomer" generally means a polymer having a finite number of constituent units based on monomers (generally 5 to 100 units) and a weight-average molecular weight greater than 1000 and less than 30000. "Polymer" means a polymer with a weight-average molecular weight of 30000 or more. The weight-average molecular weight is measured by gel permeation chromatography (GPC) and is the value obtained as a standard polystyrene equivalent.

[0026] Examples of urethane (meth)acrylates include aliphatic urethane (meth)acrylates and aromatic urethane (meth)acrylates. The weight-average molecular weight of the urethane (meth)acrylate is preferably 1,000 to 30,000, and more preferably 2,000 to 20,000. Commercially available urethane (meth)acrylates can also be used, for example, U-2PPA, U-4HA, U-6HA, U-6LPA, U-15HA, U-324A, UA-122P, UA5201, UA-512 etc. from Shin Nakamura Chemical Industry Co., Ltd.; and CN965NS, CN964A85, CN964, CN959, CN962, CN963J85, CN965, CN982B88 from ARKEMA (Sartomer). Examples include CN981, CN983, CN991, CN996, CN9002, CN9906NS, CN9007, CN9009, CN9010, CN9011, CN9178, CN9788, CN9893; and Daicel Ornex's EBECRYL230, EBECRYL270, EBECRYL8402, EBECRYL8804, EBECRYL8807, EBECRYL9270, KRM8191, etc.

[0027] An amino (meth)acrylate is a (meth)acrylate that is amine-modified and has an amino group. The number average molecular weight of the amino (meth)acrylate is preferably from 500 to 20,000, more preferably from 600 to 10,000, and even more preferably from 800 to 5,000. Commercially available products of amino (meth)acrylate can also be used. Examples include EBECRYL 7100, EBECRYL 80 manufactured by Daicel Ornex Co., Ltd., and CN551 manufactured by ARKEMA Co., Ltd. (manufactured by Sartomer Co., Ltd.).

[0028] The compound having two or more (meth)acrylate groups may be used alone or in combination of two or more. In the curable composition of the present invention, the content of the compound having two or more (meth)acrylate groups is preferably in the range of 0.5 to 20% by mass, more preferably in the range of 1 to 15% by mass, and even more preferably in the range of 2 to 12% by mass with respect to the total mass of the curable composition of the present invention. When the curable composition of the present invention contains a compound having two or more (meth)acrylate groups within such a range, the curability of the curable composition of the present invention becomes good, and the properties such as flexibility of the cured product formed from the curable composition of the present invention and adhesion to the substrate are improved. Further, when using a single compound as the compound having two or more (meth)acrylate groups, for example, a trifunctional (meth)acrylate, a tetrafunctional (meth)acrylate, etc. exemplified above, such as trimethylolpropane ethylene oxide modified triacrylate, a compound having three or more (meth)acrylate groups is used, the hardness of the cured product formed from the curable composition of the present invention increases, and the heat resistance and moisture resistance can also be effectively improved.

[0029] In addition to the (meth)acrylate having a hydroxy group and the compound having two or more (meth)acrylate groups described above, the curable composition of the present invention may further contain a (meth)acrylate having a phosphate group and a (meth)acrylate having a cyclic skeleton as the polymerizable compound (a2).

[0030] Examples of the (meth)acrylate having a phosphate group include alkylene phosphate (meth)acrylates such as methylene phosphate (meth)acrylate, ethylene phosphate (meth)acrylate, propylene phosphate (meth)acrylate, and tetramethylene phosphate (meth)acrylate; phosphate esters of polyethylene glycol monoacrylate; phosphate esters of polypropylene glycol monomethacrylate; and the like.

[0031] Commercially available products of the (meth)acrylate having a phosphate group can also be used. Examples include "EBECRYL 168" manufactured by Daicel Ornex Co., Ltd., "KAYAMER PM-2" and "KAYAMER PM-21" manufactured by Nippon Kayaku Co., Ltd.; "Hosmer M", "Hosmer PE", and "Hosmer PP" manufactured by Uniqema; "Light Ester P-1M", "Light Acrylate P-1A(N)", and "Light Ester P-2M" manufactured by Kyoeisha Chemical Co., Ltd.; "JPA-514" manufactured by Kit城北 Chemical Industry Co., Ltd.; and the like.

[0032] The (meth)acrylate having a phosphate group may be used alone or in combination of two or more. When the curable composition of the present invention contains a (meth)acrylate having a phosphate group as the polymerizable compound (a2), the amount thereof is preferably in the range of 0.1 to 10% by mass, more preferably in the range of 0.2 to 8% by mass, based on the total mass of the curable composition of the present invention. When the curable composition of the present invention contains the (meth)acrylate having a phosphate group within such a range, the curability of the curable composition of the present invention becomes good, and the performance such as the adhesion between the cured product formed from the curable composition of the present invention and the substrate is improved.

[0033] Examples of (meth)acrylates having a cyclic skeleton include (meth)acrylates having an alicyclic skeleton, monofunctional (meth)acrylates having an aromatic ring, and (meth)acrylates having a cyclic skeleton containing a heteroatom. Examples of (meth)acrylates having an alicyclic skeleton include monofunctional (meth)acrylates having a cyclic aliphatic group, such as cyclohexyl (meth)acrylate, 4-t-butylcyclohexyl (meth)acrylate, tricyclodecanedimethanol mono(meth)acrylate, adamantyl (meth)acrylate, cyclohexanedimethanol mono(meth)acrylate, trimethylcyclohexyl (meth)acrylate, isobornyl (meth)acrylate, t-butylcyclohexyl (meth)acrylate, dicyclopentanyl (meth)acrylate, and dicyclopentenyloxyethyl (meth)acrylate. Examples of monofunctional (meth)acrylates having an aromatic ring include the monomers mentioned above in polymerizable compound (a1). Examples of (meth)acrylates having a cyclic skeleton containing heteroatoms include (meth)acryloylmorpholine, N-(meth)acryloyloxyethylhexahydrophthalimide, tetrahydrofurfuryl(meth)acrylate, and cyclic trimethylolpropaneformal(meth)acrylate. Commercially available (meth)acrylates having a cyclic skeleton containing heteroatoms can also be used, such as "Viscote 150" and "Viscote 200" manufactured by Osaka Organic Chemical Industry Co., Ltd.

[0034] The (meth)acrylate having a cyclic skeleton may be used alone or in combination of two or more types. Including a (meth)acrylate having a cyclic skeleton makes it easy to adjust the viscosity of the curable composition of the present invention to a suitable viscosity range for molding by inkjet printing. Furthermore, the shrinkage of the cured product formed from the curable composition of the present invention is reduced, resulting in excellent adhesion and other properties. In this specification, a (meth)acrylate having a hydroxyl group and a cyclic skeleton is classified as a (meth)acrylate having a hydroxyl group, and a (meth)acrylate having a phosphate group and a cyclic skeleton is classified as a (meth)acrylate having a phosphate group. In addition, a monomer having two or more (meth)acrylate groups is classified as a (meth)acrylate having a hydroxyl group or a (meth)acrylate having a phosphate group if it has one or more hydroxyl groups or phosphate groups, regardless of the presence or absence of a cyclic skeleton, and is classified as a compound having two or more (meth)acrylate groups if it does not have either a hydroxyl group or a phosphate group. In other words, (meth)acrylates having a cyclic skeleton include mono(meth)acrylates that have a cyclic skeleton but do not have either a hydroxyl group or a phosphate group.

[0035] When the curable composition of the present invention contains a (meth)acrylate having a cyclic skeleton as the polymerizable compound (a2), the amount is preferably within 65% by mass, more preferably within 60% by mass, and even more preferably within 55% by mass, relative to the total mass of the curable composition of the present invention. When the curable composition of the present invention contains a (meth)acrylate having a cyclic skeleton in an amount of 60% by mass or less, the curability of the curable composition of the present invention is improved, its storage stability and the shrinkage of the formed cured product are suppressed, and performance such as adhesion to the substrate is improved. Here, when a (meth)acrylate having a cyclic skeleton is blended as the polymerizable compound (a2), such a (meth)acrylate having a cyclic skeleton may include monomers of the same type as the monofunctional (meth)acrylate having an alicyclic skeleton or the monofunctional (meth)acrylate having an aromatic ring described above as polymerizable compound (a1). In this case, the content of the cyclic skeleton (meth)acrylate in the entire curable composition of the present invention can be calculated from the total amount of monofunctional (meth)acrylate having an alicyclic skeleton or monofunctional (meth)acrylate having an aromatic ring in the polymerizable compound (a1) derived from the dispersion of the present invention and the cyclic skeleton (meth)acrylate blended as polymerizable compound (a2).

[0036] In order to achieve a balance of various properties, it is preferable that the polymerizable compound (a2) contained in the curable composition of the present invention be composed of a compound selected from the group consisting of monofunctional (meth)acrylates having a hydroxyl group, monofunctional (meth)acrylates having an aromatic group, monofunctional (meth)acrylates having an alicyclic group, and compounds having two or more (meth)acrylate groups.

[0037] Furthermore, the (meth)acrylate having a hydroxyl group, the compound having two or more (meth)acrylate groups, the (meth)acrylate having a phosphate group, and the (meth)acrylate having a cyclic skeleton described above may be compounds derived from biomass raw materials. In such cases, the curable composition of the present invention itself can be considered an environmentally conscious product, which is more preferable from the viewpoint of reducing environmental impact.

[0038] The curable composition of the present invention may further contain other polymerizable compounds different from the polymerizable compound (a2) described above. Examples of other polymerizable compounds include monofunctional polymerizable compounds or polymerizable compounds having two or more polymerizable groups (hereinafter referred to as "polyfunctional polymerizable compounds") that are different from the compounds having two or more (meth)acrylate groups described above. Here, a polymerizable group means a group having a polymerizable unsaturated double bond.

[0039] The monofunctional polymerizable compound described above is preferably a compound that has polymerizable unsaturated double bonds and is liquid at 25°C, with a molecular weight of 60 to 2000, and more preferably 100 to 1000. Furthermore, the viscosity of such a monofunctional polymerizable compound is preferably 1000 mPa·s or less, and more preferably 300 mPa·s or less. The viscosity is preferably 1 mPa·s or more, and more preferably 3 mPa·s or more.

[0040] Other polymerizable compounds mentioned above, such as monofunctional polymerizable compounds, include polymerizable compounds having a heterocyclic structure and monovinyl ether compounds. Examples of polymerizable compounds having a heterocyclic structure include N-vinylcaprolactam, N-vinylpyrrolidone, and N-vinylformamide.

[0041] Examples of monovinyl ether compounds include ethylene glycol monovinyl ether, triethylene glycol monovinyl ether, hydroxyethyl monovinyl ether, ethyl vinyl ether, n-butyl vinyl ether, isobutyl vinyl ether, octadecyl vinyl ether, cyclohexyl vinyl ether, hydroxybutyl vinyl ether, 2-ethylhexyl vinyl ether, hydroxynonyl monovinyl ether, cyclohexanedimethanol monovinyl ether, n-propyl vinyl ether, isopropyl vinyl ether, isopropenyl vinyl ether, dodecyl vinyl ether, diethylene glycol monovinyl ether, phenyl glycidyl ether, butyl glycidyl ether, and 2-ethylhexyl glycidyl ether.

[0042] Other polymerizable compounds mentioned above, such as polyfunctional polymerizable compounds, include the following general formula (1), CH ２ =CR ５ -COO-R ６ -O-CH=CH-R ７ ...(1) (wherein, R ５ R represents a hydrogen atom or a methyl group. ６ R represents an organic residue with 2 to 20 carbon atoms. ７ R represents a hydrogen atom or an organic residue having 1 to 11 carbon atoms. Examples include monomers represented by (hereinafter simply referred to as "monomer (1)"), divinyl ether compounds, trivinyl ether compounds, etc. In general formula (1), R ６ Examples of C2-C20 organic residues represented by include linear, branched, or cyclic alkylene groups having C2-C20, C2-C20 alkylene groups having oxygen atoms in their structure via ether and / or ester bonds, and C6-C11 aromatic groups where hydrogen atoms bonded to carbon atoms constituting the ring may be substituted with other substituents. C2-C6 alkylene groups and C2-C9 alkylene groups having oxygen atoms in their structure via ether bonds are preferred. ７ Examples of C1-C11 organic residues represented by include C1-C10 linear, branched, or cyclic alkyl groups, C6-C11 aromatic groups in which hydrogen atoms bonded to carbon atoms constituting the ring may be substituted with other substituents, with C1-C2 alkyl groups and C6-C8 aromatic groups being preferred.

[0043] Specific examples of monomer (1) include (meth)acrylate 2-vinyloxyethyl, (meth)acrylate 3-vinyloxypropyl, (meth)acrylate 1-methyl-2-vinyloxyethyl, (meth)acrylate 2-vinyloxypropyl, (meth)acrylate 4-vinyloxybutyl, (meth)acrylate 1-methyl-3-vinyloxypropyl, (meth)acrylate 1-vinyloxymethylpropyl, (meth)acrylate 2-methyl-3-vinyloxypropyl, (meth)acrylate 3-methyl-3-vinyl Xypropyl, 1,1-dimethyl-2-vinyloxyethyl (meth)acrylate, 3-vinyloxybutyl (meth)acrylate, 1-methyl-2-vinyloxypropyl (meth)acrylate, 2-vinyloxybutyl (meth)acrylate, 4-vinyloxycyclohexyl (meth)acrylate, 5-vinyloxypentyl (meth)acrylate, 6-vinyloxyhexyl (meth)acrylate, 4-vinyloxymethylcyclohexylmethyl (meth)acrylate, p-vinyloxymethylphenyl (meth)acrylate Methyl, 2-(vinyloxyethoxy)ethyl (meth)acrylate, 2-(vinyloxyisopropoxy)ethyl (meth)acrylate, 2-(vinyloxyethoxy)propyl (meth)acrylate, 2-(vinyloxyethoxy)isopropyl (meth)acrylate, 2-(vinyloxyisopropoxy)propyl (meth)acrylate, 2-(vinyloxyisopropoxy)isopropyl (meth)acrylate, 2-(vinyloxyethoxyethoxy)ethyl (meth)acrylate Examples include 2-(vinyloxyethoxy)ethyl methacrylate, 2-(vinyloxyethoxyisopropoxy)propyl methacrylate, 2-(vinyloxyethoxyethoxy)isopropyl methacrylate, 2-(vinyloxyethoxyisopropoxy)isopropyl methacrylate, 2-(vinyloxyethoxyethoxyethoxy)ethyl methacrylate, polyethylene glycol monovinyl ether methacrylate, and polypropylene glycol monovinyl ether methacrylate. As monomer (1), 2-(2-vinyloxyethoxy)ethyl methacrylate is preferred, and 2-(2-vinyloxyethoxy)ethyl acrylate is more preferred, from the viewpoint of low viscosity, high flash point, and excellent curability.

[0044] Examples of divinyl ether compounds or trivinyl ether compounds include ethylene glycol divinyl ether, diethylene glycol divinyl ether, triethylene glycol divinyl ether, propylene glycol divinyl ether, dipropylene glycol divinyl ether, butanediol divinyl ether, hexanediol divinyl ether, cyclohexanedimethanol divinyl ether, trimethylolpropane trivinyl ether, and the like.

[0045] If the curable composition of the present invention further contains other polymerizable compounds, one type of polymerizable compound may be used alone, or two or more types may be used in combination. Furthermore, if other polymerizable compounds are further contained, the content is preferably 30% by mass or less, more preferably 20% by mass or less, relative to the total curable composition of the present invention, and even more preferably 10% by mass or less, from the viewpoint of easily adjusting the viscosity of the resulting curable composition of the present invention and the curing shrinkage rate of the cured product of the curable composition of the present invention.

[0046] The curable composition of the present invention may be a curable composition that hardens by heat, or a curable composition that hardens by active energy rays. From the viewpoint of more suitable use as a light-shielding layer forming material for optical lenses, as described later, it is preferable that the curable composition of the present invention is a curable composition that hardens by active energy rays. For this reason, the curable composition of the present invention may further contain a photopolymerization initiator (d), and it is preferable that it contains a photopolymerization initiator (d).

[0047] Examples of photopolymerization initiators (d) include 2-methylbenzoyl diphenylphosphine oxide, bis(2,6-dichlorobenzoyl)phenylphosphine oxide, phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide, (2,4,6-trimethylbenzoyl)diphenylphosphine oxide, 2,6-dimethoxybenzoyl diphenylphosphine oxide, 2,6-dichlorobenzoyl diphenylphosphine oxide, and bis(2,6-dichlorobenzoyl)-2,5-di Acylphosphine compounds such as methylphenylphosphine oxide, bis(2,6-dichlorobenzoyl)-4-propylphenylphosphine oxide, bis(2,6-dichlorobenzoyl)-1-naphthylphosphine oxide, bis(2,6-dimethoxybenzoyl)phenylphosphine oxide, bis(2,6-dimethoxybenzoyl)-2,4,4-trimethylpentylphosphine oxide, and bis(2,6-dimethoxybenzoyl)-2,5-dimethylphenylphosphine oxide; phosphinic acid ester compounds such as methyl (2,4,6-trimethylbenzoyl)phenylphosphine, ethyl (2,4,6-trimethylbenzoyl)phenylphosphine, methyl (3-benzoyl-2,4,6-trimethylbenzoyl)phenylphosphine, ethyl (3-benzoyl-2,4,6-trimethylbenzoyl)phenylphosphine, and isopropyl pivaloylphenylphosphine;Benzoin isobutyl ether, 2,4-diethylthioxanthone [also known as 2,4-diethylthioxanthene-9-one], 2-isopropylthioxanthone, methylbenzoyl formate, 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)-butan-1-one, 1-hydroxycyclohexylphenyl ketone, benzoin ethyl ether, benzyldimethyl ketal, 2-hydroxy-2-methyl-1-phenylpropan-1-one, 1-(4-isopropylphenyl)-2-hydroxy-2-methyl Examples include propan-1-one, 2-methyl-1-(4-methylthiophenyl)-2-morpholinopropan-1-one, benzophenone, 4-phenylbenzophenone, isophthalphenone, 4-benzoyl-4'-methyldiphenyl sulfide, 2-(dimethylamino)-2-[(4-methylphenyl)methyl]-1-(4-morpholinophenyl)-butan-1-one), 1-{4-[(4-benzoylphenyl)sulfanyl]phenyl}-2-methyl-2-[(4-methylphenyl)sulfonyl]propan-1-one, etc.

[0048] Among these, phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide, (2,4,6-trimethylbenzoyl)diphenylphosphine oxide, (2,4,6-trimethylbenzoyl)ethyl phenylphosphine, and (3-benzoyl-2,4,6-trimethylbenzoyl)ethyl phenylphosphine are preferred, as they correspond to the wavelength of light emitted from an ultraviolet light-emitting diode (UV-LED) light source as the source of active energy rays. In particular, when using a UV-LED light source with a main peak wavelength of 365 to 405 nm, it is preferable to use an acylphosphine compound, especially phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide or (2,4,6-trimethylbenzoyl)diphenylphosphine oxide, as the photopolymerization initiator.

[0049] Furthermore, it is preferable that the photopolymerization initiator (d) includes an oxime-based photopolymerization initiator. When the curable composition of the present invention includes an oxime-based photopolymerization initiator as the photopolymerization initiator (d), the resulting cured product tends to have excellent heat resistance and moisture resistance. Examples of oxime-based photopolymerization initiators include J. C. S. Perkin II, 1979, pp. 1653-1660, J. C. S. Perkin II, 1979, pp. 156-162, and J. Photopolym. Sci. Tech., 1995, p. Examples of compounds described in the following publications include 202-232, JP 2000-66385, JP 2000-80068, JP 2001-233842, JP 2004-534797, JP 2006-342166, JP 2007-269779, JP 2009-191061, and JP 2012-032556. Among these, oxime compounds are preferably oxime-based photopolymerization initiators having a maximum absorption wavelength in the wavelength range of 350 nm to 500 nm, and more preferably oxime-based photopolymerization initiators having an absorption wavelength in the wavelength range of 360 nm to 480 nm. Commercial oxime-based photopolymerization initiators can be used, such as "Irgacure OXE01," "Irgacure OXE02," "Irgacure OXE03," and "Irgacure OXE04" from BASF Japan, and "TR-PBG-304" from Changzhou Strong Electronic New Materials Co., Ltd.

[0050] The photopolymerization initiator (d) may be contained as a single element or as two or more elements. When the curable composition of the present invention contains a photopolymerization initiator (d), its content is preferably 0.1 to 15% by mass, more preferably 0.5 to 12% by mass, and even more preferably 1.0 to 10% by mass, relative to the total curable composition of the present invention. When the content of the photopolymerization initiator (d) is within the above range, the curability and storage stability of the curable composition of the present invention tend to be good, and the performance of the formed cured product tends to improve.

[0051] If the curable composition of the present invention contains a photopolymerization initiator (d), the curable composition of the present invention may further contain a sensitizer. Examples of sensitizers include trimethylamine, methyldimethanolamine, triethanolamine, p-diethylaminoacetophenone, ethyl p-dimethylaminobenzoate, isoamyl p-dimethylaminobenzoate, N,N-dimethylbenzylamine, 4,4'-bis(diethylamino)benzophenone, anthracene-9,10-diethyl ether, and 9,10-bis(n-heptanoyloxy)anthracene. If the curable composition of the present invention contains a sensitizer, its content is preferably 0.1 to 10% by mass, and more preferably 0.5 to 8% by mass, relative to the total mass of the curable composition of the present invention. When the sensitizer content is within the above range, the curability of the curable composition of the present invention tends to be good, and the performance of the formed cured product tends to improve.

[0052] In addition to the components described above, the curable composition of the present invention may further optionally contain polymerization inhibitors such as hydroquinone, di-t-butylhydroquinone, p-methoxyphenol, benzoquinone, dibutylhydroxytoluene, nitrosamine salts, hindered amine compounds, and 2,2,6,6-tetramethylpiperidine 1-oxyl (TEMPO). If a polymerization inhibitor is included, the amount is preferably in the range of 0.01 to 2% by mass relative to the total amount of the curable composition of the present invention.

[0053] As described above, the curable composition of the present invention contains the dispersion of the present invention and a polymerizable compound (a2). In other words, the curable composition of the present invention contains a polymerizable compound (a1) derived from the components of the dispersion of the present invention, a black coloring agent (b), and a dispersant (c), and preferably at least one (meth)acrylate having a hydroxyl group or a compound having two or more (meth)acrylate groups as the polymerizable compound (a2), more preferably a photopolymerization initiator (d), and the above-mentioned optional components. The content of the black coloring agent (b) in the curable composition of the present invention can be controlled by the amount of the dispersion of the present invention used when preparing the curable composition of the present invention. The content of the coloring agent (b) is preferably in the range of 1 to 50% by mass, and more preferably in the range of 10 to 40% by mass, relative to the total mass of the curable composition of the present invention. When the content of the black coloring agent (b) in the curable composition of the present invention is within the above range, the dispersion of the present invention has excellent dispersibility and storage stability. Furthermore, the curable composition of the present invention, described later, containing the dispersion of the present invention becomes easier to handle, reducing the likelihood of nozzle clogging when using an inkjet method. In addition, the light transmittance of the cured product of the curable composition of the present invention can be sufficiently low, maintaining opacity, and the reflection of light incident on the cured product can be sufficiently suppressed.

[0054] The curable composition of the present invention may further contain a surfactant in order to ensure ease of handling and discharge stability applicable to inkjet methods, and to set the surface tension within a desired range. Specific examples of the surfactant are the same as those that may be contained in the dispersion of the present invention. When the curable composition of the present invention further contains a surfactant, its content is preferably 0.01 to 1% by mass, and more preferably 0.05 to 0.8% by mass, relative to the total curable composition of the present invention.

[0055] The curable composition of the present invention may further contain a leveling agent. The leveling agent makes it easier to smooth the surface of the cured product formed from the curable composition, so that the cured product hardens more uniformly when irradiated with ultraviolet light, and thus less likely to develop irregularities on the cured product. Examples of leveling agents include silane compounds, fluorine compounds, acrylic copolymers, and alcohol alkoxylate compounds. Alternatively, the surfactants mentioned above can also be used as leveling agents.

[0056] The curable composition of the present invention may further contain additives such as ultraviolet absorbers, antioxidants, surface tension modifiers, fade inhibitors, and conductive salts. Furthermore, from the viewpoint of further improving adhesion to substrates such as plastic substrates, it may also contain non-reactive resins such as acrylic resins, epoxy resins, terpene phenolic resins, and rosin esters.

[0057] The viscosity of the curable composition of the present invention at 25°C is preferably in the range of 3 to 45 mPa·s, more preferably in the range of 3 to 30 mPa·s, and more preferably in the range of 5 to 25 mPa·s. Furthermore, the surface tension of the curable composition of the present invention is preferably in the range of 15 to 45 mN / m. Having the viscosity and surface tension of the curable composition of the present invention within the above-mentioned ranges at 25°C is preferable from the viewpoint of improving the handling properties of the curable composition of the present invention and the inkjet ejection stability when molding by the inkjet method. Here, the curable composition of the present invention may further contain a solvent to adjust the viscosity, etc., within a range that does not impair the effects of the present invention, but it is preferable that it does not contain a solvent. If a solvent is not included, the drying step or heat treatment (annealing treatment) to remove the solvent when curing the curable composition of the present invention can be omitted, simplifying the manufacturing process. Furthermore, the curability is good, outgassing from the solvent from the cured product is less likely, and safety tends to be improved. Therefore, it is easier to obtain the curable composition of the present invention that can be applied by the inkjet method and does not require annealing treatment.

[0058] The curable composition of the present invention can be produced by supplying the aforementioned dispersion of the present invention, polymerizable compound (a2) [(meth)acrylate having a hydroxyl group, a compound having two or more (meth)acrylate groups, (meth)acrylate having a phosphate group, (meth)acrylate having a cyclic skeleton], a photopolymerization initiator (d), and various optional components as needed, using a conventional disperser such as a bead mill or stirrer, and then stirring and mixing. Here, in addition to a bead mill, various known and conventional dispersers can be used as the disperser, such as an ultrasonic homogenizer, high-pressure homogenizer, paint shaker, ball mill, roll mill, sand mill, sand grinder, Dyno mill, Dispermat, SC mill, nanomizer, etc.

[0059] As described above, the curable composition of the present invention is preferably a curable composition that hardens with active energy rays. Examples of active energy rays include visible light, ultraviolet light, infrared light, microwaves, EUV, semiconductor laser light, and excimer lasers (KrF, ArF). Among these active energy rays, the curable composition of the present invention is more preferably a curable composition that hardens by irradiation with light such as ultraviolet light. Examples of light sources such as ultraviolet light include metal halide lamps, xenon lamps, carbon arc lamps, chemical lamps, low-pressure mercury lamps, high-pressure mercury lamps, and UV-LED lamps. From the viewpoint of extremely low heat generation and environmental protection that can accommodate mercury-free products, it is more preferable to harden by irradiation with light from a UV-LED lamp, preferably a UV-LED lamp with a main peak wavelength of approximately 365 to 405 nm that can provide sufficient illuminance. The irradiation energy of the light using a UV-LED is 50 to 5000 mJ / cm². ２ Preferably, it is in the range of 200 to 3000 mJ / cm². ２ A range is more preferable.

[0060] When the curable composition of the present invention is used, for example, as a light-shielding layer for an optical lens of an optical element, the method of formation is not particularly limited. For example, methods include dropping the curable composition of the present invention onto the optical lens, applying it via a spin coater, die coater, dispenser, inkjet method, stencil printing method, screen printing method, gravure printing method, or mask, and then curing it.

[0061] Among these, molding using an inkjet method employing an inkjet recording method is preferred. In this case, droplets of the curable composition of the present invention can be accurately projected onto the target, thereby improving the accuracy of the shape and dimensions of the cured product. Furthermore, compared to molding using contact printing methods such as screen printing, when the curable composition of the present invention is molded using an inkjet method, foreign matter is less likely to be mixed into the curable composition and its cured product, and the yield is less likely to deteriorate when forming the light-shielding layer for the aperture of an optical lens. In addition, even if the shape of the lens is uneven, it can be formed appropriately because it is non-contact. In the inkjet method, any conventionally known method can be used as the ink ejection method, such as a method that ejects droplets using the vibration of a piezoelectric element (a recording method using an inkjet head that forms ink droplets by the mechanical deformation of an electrostrictive element), a method that utilizes thermal energy, a method that uses an actuator that utilizes electrostatic force, or a method that uses a continuously ejecting charged control type head. Furthermore, when ejecting from the inkjet head, the curable composition of the present invention can be preheated to reduce its viscosity and then molded using the inkjet method.

[0062] The curable composition of the present invention can be preferably extruded and molded by an inkjet method, and then preferably cured by irradiation with an active energy ray, such as ultraviolet light, to produce a cured product. The curable composition of the present invention is suitable as a material for forming a black layer on optical elements such as optical lenses. That is, one embodiment of the present invention is an optical element containing a cured product of the curable composition of the present invention. In particular, the curable composition of the present invention can be suitably used as a light-shielding layer-forming material for optical lenses. By using a cured product of the curable composition of the present invention, the accuracy of the dimensions and shape of the optical element can be improved, and the physical properties of the cured product of the curable composition of the present invention can be exhibited. Examples of such optical elements include optical lenses for image sensors, lenses for microscopes and telescopes, eyeglass lenses and contact lenses, or optical lenses used in display devices such as displays, projectors, mobile terminals, watches, and monitors, as well as lenses used in touch panels or lighting.

[0063] Furthermore, the applications of the curable composition of the present invention are not limited to the optical elements described above. The curable composition of the present invention can be applied to the manufacture of various products that utilize its properties, and can be used, for example, as a forming material for black light-shielding areas such as picture frames of electronic devices, or as a forming material for filters with adjustable brightness, such as ND filters.

[0064] Figure 1 schematically shows an example of the configuration of an optical lens using a cured product of the curable composition of the present invention, but is not limited thereto. Figure 1 shows a lens substrate 2 coated with a light-shielding layer 1, which is substantially circular in shape when viewed from above and has a rounded surface and some irregularities when viewed from the side. The curable composition of the present invention is applied to one side of the lens substrate 2, specifically the outer periphery, to form the light-shielding layer 1. It is also desirable to form a light-shielding layer on the edge of the lens substrate 2. As the lens substrate, in addition to transparent inorganic materials such as glass, transparent heat-resistant resin materials such as COC (cycloolefin copolymer), COP (cycloolefin polymer), or PC (polycarbonate) can be used. The size and thickness of the lens substrate 2 are not particularly limited, but from the viewpoint of balancing heat resistance, manufacturing cost, and miniaturization, a diameter of several to 100 mm and a thickness of several to 100 mm are usually preferred. The thickness of the light-shielding layer 1 is usually preferably in the range of 1 to 50 μm, more preferably in the range of 3 to 30 μm, and even more preferably in the range of 5 to 20 μm. By reducing the thickness of the light-shielding layer 1, it becomes possible to make the lens group using multiple lenses thinner. Furthermore, it is desirable that the thickness of the light-shielding layer be applied so that it is nearly constant regardless of the flat and uneven parts of the lens substrate 2, and application by a non-contact inkjet method is preferred. It is also desirable that the light-shielding layer 1 has low transmittance of incident light (high light-shielding) as well as low reflectivity at the interface with the substrate. In the present invention, by keeping the particle size of the black pigment used in the curable composition within a predetermined range, it is possible to obtain low interfacial reflectivity on the back surface of the substrate.

[0065] Figures 2 and 3 show examples of coating a curable composition onto a lens substrate 2 using an inkjet method. Figure 2 shows an example where an ultraviolet lamp 11 for curing is placed at a different position from the ink ejection head 21 of an inkjet printer that ejects the curable composition 22, and the composition is coated by irradiating it with ultraviolet light 12. In this case, the lens is rotated around its central axis 31, and the ejection of the curable composition and curing with ultraviolet light are performed sequentially. It is best to change the ink application position by gradually shifting the ink ejection head 21, and to change the position of the ultraviolet lamp 11 accordingly. Figure 3 shows an example of coating the end face of a lens with black ink. In this case, the rotation axis 31 of the lens is rotated 90 degrees from the case in Figure 2, the ink ejection head 21 is placed on the end face of the lens, and the ultraviolet lamp 11 is placed on the opposite side, and the curable composition is cured with ultraviolet light 12 immediately after coating. In this case as well, it is best to change the application position by gradually shifting the ink ejection head 21, and to change the position of the ultraviolet lamp 11 accordingly. The ultraviolet irradiation during coating shown in Figures 2 and 3 may be carried out in an oxygen-containing atmosphere such as air, or in an inert atmosphere such as a nitrogen atmosphere.

[0066] The dispersion, curable composition, cured product of the curable composition of the present invention, method for producing the same, and an embodiment of an optical element containing the cured product of the present invention have been described above. However, the present invention is not limited to the configuration of the embodiment described above. For example, the curable composition of the present invention may have additional configurations of any other choice in the configuration of the above embodiment, or may be replaced with any configuration that produces a similar effect.

[0067] The present invention will be specifically described below with reference to examples and comparative examples, but the present invention is not limited to these examples. The compounds used in these examples are shown below.

[0068] <Polymerizable compound a1> a1-1: Miramer M1182 (trade name, manufactured by MIWON, benzyl acrylate (monofunctional (meth)acrylate), viscosity (25°C) 1-10 mPa·s) a1-2: Viscoat 196 (trade name, manufactured by Osaka Organic Chemical Industry Co., Ltd., 3,3,5-trimethylcyclohexyl acrylate (meth)acrylate with an alicyclic skeleton), viscosity (25°C) 1-10 mPa·s) <Coloring agent (b)> b-1: Carbon black, #960 (manufactured by Mitsubishi Chemical Corporation) b-2: Carbon black, MA11 (manufactured by Mitsubishi Chemical Corporation) b-3: Carbon black, MA220 (manufactured by Mitsubishi Chemical Corporation) b-4: Bisbenzofuranone type, Irgaphor Black S0100CF (manufactured by BASF) b-5: Perylene-based, Spectrasense Black EH8082 (manufactured by Sun Chemical) <Dispersant (c)> c-1: "EFKA® PX4701" (manufactured by BASF, acrylic block copolymer) c-2: "Solsperse® 39000" (manufactured by Lubrizol)

[0069] <Polymerizable Compounds a2> <(meth)acrylates having aromatic rings> a2-1: Light Acrylate PO-A (trade name, manufactured by Kyoeisha Chemical Co., Ltd., phenoxyethyl acrylate (monofunctional (meth)acrylate), viscosity (25°C) 8-20 mPa·s) <(meth)acrylates having an alicyclic skeleton> a2-2: Viscoat 196 (trade name, manufactured by Osaka Organic Chemical Industry Co., Ltd., 3,3,5-trimethylcyclohexyl acrylate (meth)acrylate having an alicyclic skeleton), viscosity (25°C) 1-10 mPa·s) <(meth)acrylates having hydroxyl groups> a2-3: 4-HBA (trade name, manufactured by Osaka Organic Chemical Industry Co., Ltd., 4-hydroxybutyl acrylate, viscosity (25°C) 5.5 mPa·s) <Compounds having two or more (meth)acrylate groups> a2-4: Miramer M320 (Trade name, manufactured by MIWON, glycerin propylene oxide added triacrylate, viscosity (25°C) 80-120 mPa·s) a2-5: EBECRYL80 (manufactured by Daicel Ornex, amine-modified highly reactive polyether acrylate, viscosity (25°C) up to 3000 mPa·s) a2-6: EBECRYL7100 (manufactured by Daicel Ornex, amino acrylate acrylate, viscosity (25°C) up to 1200 mPa·s)

[0070] <Photopolymerization Initiators> d-1: TPO-L [(2,4,6-trimethylbenzoyl)diphenylphosphine oxide; manufactured by IGM RESINS B.V.] d-2: Omnirad 819 [Phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide; (acylphosphine oxide type, manufactured by IGM RESINS B.V.)] d-3: Kayacure DETX-S [2,4-diethylthioxanthene-9-one (manufactured by Nippon Kayaku Co., Ltd.)] d-4: Kayacure EPA [p-dimethylaminobenzoate ethyl (manufactured by Nippon Kayaku Co., Ltd.); sensitizer]

[0071] <Polymerization inhibitor> Nonflex Alba: 2,5-di-t-butylhydroquinone (manufactured by Seiko Chemical Co., Ltd.) <Additives (leveling agents)> e-1: KF-54: Polyether-modified polysiloxane (manufactured by Shin-Etsu Chemical Co., Ltd.) e-2: BYK-UV3500: Acrylic group-containing polyether-modified polydimethylsiloxane (manufactured by BYK Corporation)

[0072] 1. Preparation of Dispersion [Example 1-1] 82 parts by mass of polymerizable compound (a1-1), 10 parts by mass of colorant (b-1), and 8 parts by mass of dispersant (c-1) were placed in a polypropylene container. 300 parts by mass of 0.3 mm zirconia beads were then added, and the mixture was shaken and dispersed using a paint conditioner (manufactured by Toyo Seiki Seisakusho, also known as a paint shaker) to obtain dispersion D1. The viscosity of dispersion D1 at 25°C was measured using an E-type viscometer (TVE-25L: manufactured by Toki Sangyo Co., Ltd.) and was found to be 30 mPa·s, which was sufficiently low. Furthermore, dispersion D1 was diluted 8000 times with methyl ethyl ketone, and the D50 of the colorant (b-1) was measured using a nanoparticle size measuring device Nano Track Wave II (manufactured by Micro Track Bell), which was found to be 81 nm. [Examples 1-2 to 1-5] Polymerizable compound (a1-1) or polymerizable compound (a1-2), colorant (b-2) to (b-5), and dispersant (c-1) or (c-2) were dispersed in the same manner as in Example 1-1 to obtain dispersions D2 to 5 having the component content ratios shown in Table 1.

[0073]

[0074] 2. Preparation of Curable Composition [Example 1] 44.4% by mass of the dispersion D3 obtained in Examples 1-3, 11.1% by mass of polymerizable compounds (a2), 14.1% by mass of (a2-1), 16.8% by mass of (a2-3), and 5.3% by mass of (a2-4), 7.1% by mass of (d-2) and 0.9% by mass of (d-3) as photopolymerization initiators (d), 0.1% by mass of polymerization inhibitor, and 0.1% by mass of leveling agent (e-2) were placed in a container and stirred to prepare curable composition 1. The content of each component of curable composition 1 is shown in Table 2. [Examples 2 and 3] The dispersions D4 and D5 obtained in Examples 1-4 and 1-5, polymerizable compound (a2), photopolymerization initiator (d), polymerization inhibitor, and leveling agent (e) were placed in a container and stirred to prepare curable compositions 2 and 3 having the component content ratios shown in Table 2. [Comparative Examples 1 and 2] The dispersions D1 and D2 obtained in Examples 1-1 and 1-2, polymerizable compound (a2), photopolymerization initiator (d), polymerization inhibitor, and leveling agent (e) were placed in a container and stirred to prepare curable compositions 4 and 5 having the component content ratios shown in Table 2. 3. Evaluation 3-1. Viscosity of Curable Compositions Viscosity was measured using an E-type viscometer (TVE-25L: manufactured by Toki Sangyo Co., Ltd.) at a temperature of 25°C. The viscosity of each curable composition is shown in Table 1 using the following evaluation index. [Evaluation Index] A: 20 mPa·s or less. B: greater than 20 mPa·s and 30 mPa·s or less. C: greater than 30 mPa·s. Furthermore, when each curable composition was stored in the range of -20 to 20°C, the viscosity change was small, and all exhibited good storage stability.

[0075] 3-2. Light transmittance of cured material (1) The curable composition obtained in each example was applied to a substrate (50 mm long x 50 mm wide, 2 mm thick) using a spin coater to a film thickness of approximately 5 μm to create a coating. This coating was then exposed to UV-LED irradiation using an ITEC Systems Co., Ltd., with a peak wavelength of 365 nm and a peak illuminance of 3000 mW / cm². ２ , cumulative light intensity 3 J / cm ２The cured material (cured coating) was prepared by irradiating it with ultraviolet light under the specified conditions. (2) The light transmittance of each cured material obtained above at wavelengths of 400 to 800 nm was measured using a spectrometer (LCD-5200 manufactured by Otsuka Electronics Co., Ltd.). The measured light transmittance of the substrate alone before coating, which was used during the preparation of the cured material, was used as a reference value. All cured materials were almost black. The light transmittance values ​​of each cured material at 550 nm are shown in Table 1.

[0076] 3-3. Back surface reflectance of cured material The reflectance of the substrate prepared in 3-2. was measured using a Hitachi U-4100 spectrophotometer (manufactured by Hitachi High-Tech Fielding Co., Ltd., optical measurement using an integrating sphere). Figure 4 schematically shows the method for measuring the back surface reflectance of the cured material. The configuration includes an integrating sphere 101 between the measurement light source 102 and the lens substrate 2 coated with the light-shielding layer 1, which is the object to be measured for back surface reflectance. Using the curable composition of the present invention, the coated surface of the light-shielding layer 1 of the lens substrate 2 was placed outside the integrating sphere, and the reflectance was measured with the lens substrate 2 facing the integrating sphere side. This allows for a comparison of the difference in reflectance at the interface between the substrate and the light-shielding film. The reflectance measured in this measurement is called the back surface reflectance. 3-4. Adhesion of cured material Cured material (cured coating film) of the curable composition obtained in each manufacturing example was prepared in the same manner as in 3-2 (1), and a grid pattern of cuts was made on its surface using a cutter. Next, adhesive tape (manufactured by Nichiban Co., Ltd.) was applied to the surface and then peeled off. The remaining state of the hardened film on the substrate was visually observed, and the adhesion was evaluated according to the following criteria: [Evaluation Criteria] A: No peeling of the hardened coating was observed. B: Some peeling was observed. C: Significant peeling was observed.

[0077] 3-5. Moisture Resistance of Cured Products In the same manner as in 3-2(1), cured products (cured coating films) were prepared from the curable compositions obtained in each manufacturing example, and each cured product was placed in a constant temperature bath at 85°C and 85% relative humidity for 500 hours. After removing the cured products and allowing them to cool naturally to 25°C, the presence or absence of surface non-uniformity was observed using a microscope (magnification 100x), and the moisture resistance was evaluated according to the following criteria. [Evaluation Criteria] A: No change B: Non-uniformity of the surface of the cured product is observed by microscopic observation at 100x magnification. C: Non-uniformity of the surface of the cured product can be confirmed visually without the need for microscopic observation.

[0078] Table 1 summarizes the mass ratio of each component in each curable composition and the evaluation results described above. Table 2 also shows the proportion of compounds having two or more (meth)acrylate groups relative to the total mass of the curable composition (polyfunctional compound ratio; mass%) and the proportion of photopolymerization initiator (d) relative to the total mass of the curable composition (photopolymerization initiator (d) ratio; mass%) for each example curable composition.

[0079]

[0080] Figure 5 shows the results of measuring the wavelength dispersion of back surface reflectance when the ink of Example 1 was applied to a PC substrate and a 5 μm thick light-shielding layer was provided. From the reflectance graph of wavelength dispersion shown here, the reflectance of light at a wavelength of 550 nm was read, and Figure 6 shows a graph plotting the back surface reflectance of light at a wavelength of 550 nm when the curable composition described in each example and comparative example was applied to a PC substrate and a 5 μm thick light-shielding layer was provided. In the visible range, the lower this back surface reflectance, the less reflection at the interface there is, resulting in less stray light and scattered light, which is a more desirable form. Generally, for optical elements, a small back surface reflectance is preferable. From the examples and comparative examples, the larger the average particle size (D50), the lower the back surface reflectance. The minimum back surface reflectance is at 8%, and in the region where the change in back surface reflectance due to the average particle size (D50) is less than 1.0%, the reflectance is sufficiently low and can be maintained at high quality. Looking at the dispersed particle size that accounts for this increase of less than 1.0%, it can be seen that it is sufficient to control the particle size to a large particle size of 150 nm or more. To reduce the back surface reflectance, it is preferable to use a black pigment with an average particle size of 200 nm or more, and to further reduce it, it is preferable to use a black pigment with an average particle size of 250 nm or more. Similarly, in the case of the COC substrate, the back surface reflectance can be reduced as the average particle size increases, and as with the PC substrate, a black pigment with an average particle size of 150 nm or more is preferable, a black pigment with an average particle size of 200 nm or more is preferable, and more preferably a black pigment with an average particle size of 250 nm or more is preferable. These results indicate that a curable composition containing a dispersion of polymerizable compound (a1) a monofunctional (meth)acrylate having a cyclic skeleton, a black coloring agent (b) a pigment with an average particle size (D50) in the range of 150 to 500 nm, and a dispersant (c), and containing polymerizable compound (a2) a (meth)acrylate having a hydroxyl group and a compound having two or more (meth)acrylate groups, and preferably containing a predetermined amount or more of a photopolymerization initiator, has low viscosity and is easy to handle, and exhibits excellent adhesion to the substrate and moisture resistance of the cured product. In particular, the light transmittance of the cured product at a film thickness of around 5 μm is in the range of 0.1 to 0.9%, indicating excellent low light transmittance (opacity). Furthermore, it can be seen that the back surface reflectance of the cured product is suppressed. A cured film made from such a curable composition of the present invention is suitable as a light-shielding layer material for optical lenses.On the other hand, it was found that cured products of curable compositions containing black pigments with an average particle size (D50) of 150 nm or less exhibit a higher back surface reflectivity and poorer adhesion to the substrate.

[0081] The curable composition of the present invention exhibits excellent curability, enabling the formation of molded products by inkjet printing. The resulting cured product has excellent low light transmittance (opacity), low reflectivity, adhesion to substrates, and moisture resistance. The curable composition of the present invention is particularly suitable as a composition for optical element materials and is useful as a material for aperture shielding (opacity) in optical lenses. Furthermore, optical elements using cured products of the curable composition of the present invention are useful as optical lenses for image sensors, lenses for microscopes and telescopes, eyeglass lenses and contact lenses, or optical lenses used in display devices such as displays, projectors, mobile terminals, watches, and monitors, as well as lenses used in touch panels or lighting.

[0082] 1. Light-shielding layer 2. Lens substrate 3. Aperture 11. Ultraviolet lamp 12. Ultraviolet light 21. Ink ejection head 22. Curable composition 31. Rotating shaft 101. Integrating sphere 102. Measurement light source

Claims

1. A dispersion containing a polymerizable compound (a1), a black coloring agent (b), and a dispersant (c), wherein the average particle size (D50) of the coloring agent (b) is in the range of 150 to 500 nm.

2. The dispersion according to claim 1, wherein the polymerizable compound (a1) contains a monofunctional (meth)acrylate.

3. The dispersion according to claim 2, wherein the monofunctional (meth)acrylate is a monofunctional (meth)acrylate having a cyclic skeleton.

4. The dispersion according to claim 1, wherein the black coloring agent (b) contains a black pigment.

5. A curable composition comprising the dispersion described in claim 1 and a polymerizable compound (a2).

6. The curable composition according to claim 5, wherein the polymerizable compound (a2) contains a (meth)acrylate having a hydroxyl group.

7. The curable composition according to claim 5 or 6, further comprising a photopolymerization initiator (d).

8. The curable composition according to claim 7, wherein the photopolymerization initiator (d) comprises an acylphosphine-based photopolymerization initiator.

9. The curable composition according to claim 5, wherein the content of the black coloring agent (b) is 3 to 40% by mass with respect to the total mass of the curable composition.

10. The curable composition according to claim 5, which is an active energy ray curable composition.

11. The curable composition according to claim 5, which does not contain a solvent.

12. The curable composition according to claim 5, which is a light-shielding composition for optical lenses.

13. A cured product of a curable composition according to any one of claims 5 to 12.

14. A method for producing a cured product, comprising the step of curing a curable composition according to any one of claims 5 to 12 by irradiating it with active energy rays.

15. The manufacturing method according to claim 14, wherein the curable composition is molded by an inkjet method.

16. An optical lens with a light-shielding material, using a cured product of the curable composition according to any one of claims 5 to 12.

17. An optical lens with a light-shielding material according to claim 16, wherein the base material is one of the following: cyclic olefin copolymer (COC), cycloolefin polymer (COP), or polycarbonate resin (PC).

18. A camera module comprising an optical lens with a light-shielding material as described in claim 17.

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