Near-infrared ray-transmissive black particles

Abstract

The present invention provides a near-infrared transmitting black particle having high transmittance in the near-infrared region and low transmittance in the visible region. The present invention relates to a near-infrared transmitting black particle having a transmittance T 600 (%) at a wavelength of 600 nm measured using a spectrophotometer and a transmittance T 900 (%) at a wavelength of 900 nm satisfying the following relation of Expression (1). T 900 - T 600 ≥ 60 (1).

Description

Technical Field

[0001] This invention relates to near-infrared transmission black particles. Background Technology

[0002] Carbon black has traditionally been used as a black material, with other materials such as iron oxide black (Fe3O4) also employed. These materials exhibit a black color and absorb light wavelengths from the visible to the far-infrared region. Therefore, coatings and other items colored with these black materials tend to become hot due to the absorption of sunlight. Furthermore, carbon black is conductive, resulting in items colored with it lacking electrical insulation properties.

[0003] On the other hand, in recent years, in the fields of electronic devices and optical devices, due to the utilization of infrared laser radiation and the corresponding advancements in sensors, there is an increasing demand for black materials with properties not found in traditionally used black materials such as carbon black.

[0004] For example, oil-soluble dyes are used as coloring materials for infrared transmissive filters in infrared communication, infrared camouflage, and optical filters. However, these oil-soluble dyes have problems with durability, such as heat resistance, solvent resistance, and light resistance. Therefore, there is a search for dark-colored materials with excellent durability and superior infrared transmissivity. Furthermore, from an energy-saving perspective, heat-reflecting coatings that reflect sunlight are desired. Heat-reflecting materials for this purpose are expected to be used as coatings for roofs and walls of structures, road paving, automotive exteriors and interiors, and as heat-generating materials such as coatings for electronic components. Additionally, they are expected to be used as heat-reflecting materials for agricultural applications, such as insulation materials.

[0005] In particular, black materials with sufficient transmittance to light with wavelengths from near-infrared to infrared are being put into practical use. For example, Patent Document 1 describes a dark azo pigment obtained by using 2-hydroxy-11H-benzo[a]carbazole-3-carboxy-N-benzimidazolone-5-amide as a coupling component and a known diazo compound as a diazo component, and by coupling the two.

[0006] Furthermore, Patent Document 2 describes a black material with a volume fraction of 2% to 30% and an average dispersed particle size of 1 nm to 200 nm, an optical density of 1 or more per 1 μm thickness, and a volume resistivity of 10. 11 A black film with an Ω·cm or higher.

[0007] Existing technical documents

[0008] Patent documents

[0009] Patent Document 1: International Publication No. 2010 / 044393

[0010] Patent Document 2: International Publication No. 2012 / 026577 Summary of the Invention

[0011] The problem that the invention aims to solve

[0012] However, even with regard to the materials in Patent Documents 1 and 2, the near-infrared transmittance is still insufficient. Furthermore, there is the problem of increased visible light transmittance.

[0013] Therefore, in Patent Document 1 and Patent Document 2, there are situations where the design of the coating film is limited by the need to make the formed coating film thicker or to increase the amount of black material added in order to block visible light.

[0014] In view of the above-mentioned situation, the present invention aims to provide: near-infrared transmissive black particles with high transmittance in the near-infrared region and low transmittance in the visible light region.

[0015] Methods for solving problems

[0016] This disclosure (1) is a near-infrared transmissive black particle, whose transmittance T at a wavelength of 600 nm is measured using a spectrophotometer. 600 (%) and transmittance T at a wavelength of 900 nm 900 (%) satisfies the relationship of the following equation (1).

[0017] T 900 -T 600 ≥60 (1)

[0018] This disclosure (2) relates to the near-infrared transmission black particles described in this disclosure (1), wherein, T 600 Less than 10%, and T 900 Greater than 80%.

[0019] This disclosure (3) relates to the near-infrared transmissive black particles described in disclosure (1) or (2), wherein the diffusion transmittance Td at a wavelength of 900 nm, as measured using a spectrophotometer, is... 900 (%) is below 10%.

[0020] This disclosure (4) relates to the near-infrared transmissive black particles described in any one of disclosures (1) to (3), wherein the diffusion transmittance Td at a wavelength of 1100 nm, as measured using a spectrophotometer, is... 1100 (%) is below 10%.

[0021] This disclosure (5) relates to near-infrared transmission black particles described in any one of disclosures (1) to (4), which contain: a copolymer having structural units derived from compounds having aromatic rings containing hydroxyl groups and structural units derived from compounds containing amino groups.

[0022] This disclosure (6) relates to the near-infrared transmission black particles described in any one of disclosures (1) to (5), which contain a crosslinking agent.

[0023] This disclosure (7) relates to near-infrared transmission black particles described in any of disclosures (1) to (6), wherein the copolymers having structural units derived from compounds having aromatic rings containing hydroxyl groups and structural units derived from amino compounds contain auxochromes.

[0024] The present invention will now be described in detail.

[0025] The inventors conducted in-depth research and found that by increasing the transmittance T at a wavelength of 600 nm... 600 and the transmittance T at a wavelength of 900 nm 900 By satisfying the specified relationship, near-infrared transmissive black particles with high transmittance in the near-infrared region and low transmittance in the visible light region can be obtained, thus completing the present invention.

[0026] Regarding the near-infrared transmissive black particles of the present invention, the transmittance T at a wavelength of 600 nm was measured using a spectrophotometer. 600 (%) and transmittance T at a wavelength of 900 nm 900 (%) satisfies the following relationship (1) (Hereinafter, the transmittance at wavelength λnm is denoted as T) λ (%)).

[0027] T 900 -T 600 ≥60 (1)

[0028] By satisfying the above relationship, it is possible to produce near-infrared transmissive black particles with high transmittance in the near-infrared region and low transmittance in the visible light region.

[0029] The above "T" 900 -T 600 "Preferably 65% ​​or more, more preferably 70% or more."

[0030] The above "T" 900 -T 600 There is no specific upper limit for "", the higher the better, with an optimal upper limit of 100%.

[0031] The above T 600 And T 900For example, measurements can be performed using a spectrophotometer with an integrating sphere, with a reflector mounted on the opposite side of the light incident side (hereinafter, T). 850 T 800 T 600 (The same measurement method is also used). In addition, in this specification, the term "transmittance" refers to "total transmittance," which is different from "diffusion transmittance" as described later.

[0032] In addition, as a measure of the above T 600 And T 900 For the sample, a glass plate was obtained by mixing the near-infrared transmission black particles of the present invention with polyvinyl acetal resin at a ratio of 1:9, dissolving the mixture in a solvent, coating the solution onto the glass plate, and allowing the solvent to dry to form a coating film with a thickness of 30 μm.

[0033] Furthermore, from the viewpoint of making the transmittance of the infrared region higher and the transmittance of the visible light region lower, it is preferable to satisfy the following formula (2), and more preferably to satisfy the following formula (3).

[0034] T 850 -T 600 ≥60 (2)

[0035] T 800 -T 600 ≥50 (3)

[0036] The above "T" 850 -T 600 "Preferably 65% ​​or more, more preferably 70% or more. The above-mentioned 'T'..." 850 -T 600 There is no specific upper limit for "", the higher the better, with an optimal upper limit of 100%.

[0037] The above "T" 800 -T 600 "Preferably 55% or more, more preferably 60% or more. The above-mentioned 'T'..." 800 -T 600 There is no specific upper limit for "", the higher the better, with an optimal upper limit of 100%.

[0038] For the near-infrared transmission black particles of the present invention, the above-mentioned T 600 Preferably less than 10%, more preferably less than 5%. By setting it within the above range, visible light blocking is improved, and defects such as filter decolorization and sensor malfunction are reduced. Furthermore, the aforementioned T... 600 The lower limit is not specifically limited, but is preferably 0%.

[0039] In addition, the above T 900Preferably greater than 80%, more preferably greater than 85%. By setting the above range, the working efficiency of the sensor can be improved. It should be noted that the above T 900 is not particularly limited in upper limit, but is preferably 100%.

[0040] For the near-infrared transmitting black particles of the present invention, the diffuse transmittance Td at a wavelength of 900 nm measured using a spectrophotometer 900 (%) is preferably 10% or less. By setting the above range, the diffusion of near-infrared light is suppressed, the use efficiency of the transmitted near-infrared light becomes higher, and the near-infrared light can be effectively utilized. In addition, the above Td 900 is more preferably 3% or less. It should be noted that the above Td 900 is not particularly limited in lower limit, but is preferably 0%.

[0041] For the near-infrared transmitting black particles of the present invention, the diffuse transmittance Td at a wavelength of 1100 nm measured using a spectrophotometer 1100 (%) is preferably 10% or less. By setting the above range, the diffusion of near-infrared light is suppressed, the use efficiency of the transmitted near-infrared light becomes higher, and the near-infrared light can be effectively utilized. In addition, the above Td 1100 is more preferably 3% or less. It should be noted that the above Td 1100 is not particularly limited in lower limit, but is preferably 0%.

[0042] The above Td 900 , Td 1100 can be measured, for example, by using a spectrophotometer equipped with an integrating sphere, removing the reflection plate on the opposite side facing the light incident side, so that only diffused light remains in the integrating sphere.

[0043] For the near-infrared transmitting black particles of the present invention, "T 900 - T 600 ", "T 850 - T 600 ", "T 800 - T 600 ", "T 600 ", "T 900 ", "Td 900 ", "Td 1100 " can be adjusted in numerical ranges through the composition, content ratio, polymerization reaction and the like of the copolymer having a structural unit derived from a compound having a hydroxyl group-containing aromatic ring and a structural unit derived from an amino group-containing compound, and the crosslinking agent.

[0044] The near-infrared transmitting black particles of the present invention preferably contain a copolymer having a structural unit derived from a compound having a hydroxyl group-containing aromatic ring and a structural unit derived from an amino group-containing compound.

[0045] By incorporating the aforementioned copolymer, it is possible to produce near-infrared transmissive black particles that have high transmittance in the near-infrared region and low transmittance in the visible light region.

[0046] Examples of aromatic rings include benzene rings, naphthalene rings, and anthracene rings. Among these, benzene rings and naphthalene rings are preferred.

[0047] Examples of compounds having a hydroxyl-containing naphthalene ring include 1-naphthol, 2-naphthol, dihydroxynaphthalene, trihydroxynaphthalene, tetrahydroxynaphthalene, and pentahydroxynaphthalene. Among these, dihydroxynaphthalene and 1-naphthol are preferred, and among dihydroxynaphthalenes, 1,3-dihydroxynaphthalene, 1,5-dihydroxynaphthalene, and 1,6-dihydroxynaphthalene are preferred.

[0048] In addition, examples of compounds having a benzene ring containing a hydroxyl group include: phenol and its derivatives, catechol, resorcinol, hydroquinone and its derivatives, pyrogallol, resorcinol, pyrogallol and its derivatives, tetrahydroxybenzene and its derivatives, etc.

[0049] Regarding the aforementioned compounds containing hydroxyl-containing aromatic rings, it is preferable to use multiple combinations thereof. In this case, it is preferable to use combinations of different compounds containing hydroxyl-containing aromatic rings, and more preferably, combinations of compounds containing hydroxyl-containing naphthalene rings and compounds containing hydroxyl-containing benzene rings. This allows for the expression of the incompatible properties of visible light blocking due to the naphthalene ring and near-infrared transmission due to the benzene ring. Furthermore, multiple combinations of compounds containing hydroxyl-containing naphthalene rings can also be used.

[0050] The hydroxyl group bonded to the aromatic ring exhibits the nucleophilicity of the aromatic ring (becoming the starting point for nucleophilic attack on the aromatic ring), therefore it is preferable to have a hydrogen atom at the ortho and / or para positions of the hydroxyl group (in the case of compounds with a hydroxyl-containing naphthalene ring, at the ortho and / or para positions of the hydroxyl group on the substituted benzene ring). This allows for a complete attack.

[0051] Specifically, regarding the hydroxyl-containing naphthalene ring, when there is one hydroxyl group, if the hydroxyl group is substituted at position 1, it is preferable that positions 2 and / or 4 are only unsubstituted hydrogens; if the hydroxyl group is substituted at position 2, it is preferable that positions 1 and / or 3 are only unsubstituted hydrogens. When there are two hydroxyl groups, if one hydroxyl group is substituted at position 1, it is preferable that positions 2 and 4 are only unsubstituted hydrogens, and the second hydroxyl group is substituted at positions 5, 6, 7, and 8; if one hydroxyl group is substituted at position 2, it is preferable that positions 1 and 3 are only unsubstituted hydrogens, and the second hydroxyl group is substituted at positions 5, 6, 7, and 8.

[0052] Specifically, it is preferred to have any of the structures in equations (4) and (5) below.

[0053] By setting the structure in this way, it is possible to maintain the highly nucleophilic and aggressive state of the aromatic ring derived from the hydroxyl group.

[0054] [Chemical Formula 1]

[0055]

[0056] In formulas (4) and (5), R1, R2, R3, and R4 represent hydrogen or alkyl groups with 20 or fewer carbon atoms.

[0057] Furthermore, the compounds having a hydroxyl-containing benzene ring preferably have 1 to 3 hydroxyl groups, and the compounds having a hydroxyl-containing naphthalene ring preferably have 1 to 4 hydroxyl groups. This allows them to maintain general nucleophilic attack.

[0058] The aforementioned amino-containing compounds function as electron-donating auxochromes for compounds with hydroxyl-containing aromatic rings that are chromophores.

[0059] Therefore, in addition to amino groups, the above-mentioned amino-containing compounds may also have ether groups, hydroxyl groups, etc.

[0060] Furthermore, there is no particular limitation as long as the above-mentioned amino-containing compounds are amino-containing compounds. Examples include compounds containing primary, secondary, and tertiary amino groups, but compounds containing primary amino groups are preferred.

[0061] In addition to ammonia and hydrazine, chain aliphatic amines, alicyclic amines, aromatic amines, alkanolamines, etc., can be used as the above-mentioned amino-containing compounds.

[0062] Among them, aromatic amines are preferred.

[0063] Examples of aromatic amines include aromatic monoamines and aromatic polyamines.

[0064] Examples of aromatic monoamines include aniline, p-toluidine, p-ethylaniline, p-anisidine, α-naphthylamine, p-butylaniline, p-aminophenethyl ether, and 4-aminophenol. Among these, aniline and p-anisidine are preferred.

[0065] Examples of aromatic polyamines include N,N-dimethyl-1,4-phenylenediamine, toluene diamine, and 4,4'-diaminodiphenylmethane.

[0066] In particular, among the above-mentioned aromatic polyamines, it is preferred that the first amino group is a primary amino group without substituents, and that an electron-donating alkyl, amino, or alkoxy group is located at the ortho or para position, more preferably at the para position, of the amino group. Regarding the second or subsequent amino or alkoxy group that is substituted at the para position, it is preferred that the alkyl group is substituted without active hydrogen. Specifically, it is preferable to have a structure of the following formula (6).

[0067] [Chemical Formula 2]

[0068]

[0069] In equation (6), R X "-" indicates hydrogen, "-OR" or "-NR'R", "R", "R'", and "R" indicate alkyl groups with 20 or fewer carbon atoms.

[0070] Examples of the aforementioned chain-like aliphatic amines include: ethylamine, 1-propylamine, 2-propylamine, 1-butylamine, 1-pentylamine, 1-hexylamine, 1-heptylamine, 1-octylamine, as well as 1-laurhodium, 1,2-ethanediamine, 1,3-propanediamine, 1,4-butanediamine, 1,5-pentanediamine, 1,6-hexanediamine, ethylenetriamine, diethylenetriamine, ethylhydrazine, 1-propylhydrazine, 1-butylhydrazine, 1-pentylhydrazine, 1-hexylhydrazine, 1-heptylhydrazine, 1-octylhydrazine, succinate dihydrazine, terephthalate dihydrazine, guanidine, 1-butylguanidine, 1-cyanoguanidine, dicyandiamide, etc.

[0071] Examples of the aforementioned alicyclic amines include: cyclopropylamine, cyclobutylamine, cyclopentylamine, cyclohexylamine, cyclopropanediamine, isophoronediamine, cyclobutanediamine, cyclopentanediamine, cyclohexanediamine, bis(4-aminocyclohexyl)methane, piperazine, N-aminoethylpiperazine, etc.

[0072] In addition, examples of alkanolamines include monoethanolamine, diethanolamine, and triethanolamine.

[0073] The aforementioned amino-containing compounds preferably have 1 to 3 amino groups. This allows for sufficient reaction between the amino groups and the aromatic ring containing the hydroxyl group. Furthermore, by setting the number of amino groups to 3 or fewer, the basicity of each amino group can be set to a suitable level. Moreover, from the viewpoint of minimizing steric hindrance to reactivity, the amino groups are preferably located at the ends of the molecule.

[0074] The copolymers having structural units derived from compounds having aromatic rings containing hydroxyl groups and structural units derived from compounds containing amino groups preferably contain auxochromes.

[0075] In addition to the amino group, other auxochromes mentioned above include thiol groups, aldehyde groups, carboxyl groups, and hydroxyl groups. There may be only one type of auxochrome or two or more types.

[0076] The near-infrared transmission black particles of the present invention preferably contain a crosslinking agent.

[0077] By using the aforementioned crosslinking agent, the copolymer having structural units derived from compounds containing hydroxyl-containing aromatic rings and structural units derived from amino-containing compounds is crosslinked, enabling the production of black particles with excellent processability due to resinification of the constituent elements. In this case, the copolymer has a structure having structural units derived from compounds containing hydroxyl-containing aromatic rings, structural units derived from amino-containing compounds, and structural units derived from the crosslinking agent.

[0078] It should be noted that the crosslinking agent mentioned above is different from the compounds with hydroxyl-containing aromatic rings and the compounds containing amino groups.

[0079] As the crosslinking agent mentioned above, an electrophilic reactant that is easily subjected to phenolic nucleophilic attack is preferred.

[0080] Examples of crosslinking agents include: polyamine-based crosslinking agents, thiourea-based crosslinking agents, thiadiazole-based crosslinking agents, triazine-based crosslinking agents, quinoxaline-based crosslinking agents, bisphenol-based crosslinking agents, organic peroxide-based crosslinking agents, aldehyde-based crosslinking agents, and silane-based crosslinking agents. Additionally, phenolic crosslinking agents such as methylphenolic resins can also be used.

[0081] Examples of polyamine crosslinking agents include: ethylenediamine, hexamethylenediamine, diethylenetriamine, triethylenetetramine, hexamethylenetetramine, p-phenylenediamine, isopropylphenylenediamine, N,N'-biscinnamaldehyde-1,6-hexanediamine, ethylenediamine carbamate, and hexamethylenediamine carbamate.

[0082] Examples of thiourea-based crosslinking agents include: 2-mercaptoimidazoline (ethylidene thiourea), 1,3-diethylthiourea, 1,3-dibutylthiourea, trimethylthiourea, etc.

[0083] Examples of thiadiazole-based crosslinking agents include 2,5-dimercapto-1,3,4-thiadiazole and 2-mercapto-1,3,4-thiadiazole-5-thiobenzoate.

[0084] Examples of triazine-based crosslinking agents include: 2,4,6-trimercapto-1,3,5-triazine, 2-hexylamino-4,6-dimercaptotriazine, 2-diethylamino-4,6-dimercaptotriazine, 2-cyclohexylamino-4,6-dimercaptotriazine, 2-dibutylamino-4,6-dimercaptotriazine, 2-aniline-4,6-dimercaptotriazine, and 2-phenylamino-4,6-dimercaptotriazine.

[0085] Examples of quinoxaline-based crosslinking agents include 2,3-dimercaptoquinoxaline, quinoxaline-2,3-dithiocarbonate, 6-methylquinoxaline-2,3-dithiocarbonate, and 5,8-dimethylquinoxaline-2,3-dithiocarbonate.

[0086] Examples of bisphenol-based crosslinking agents include bisphenol AF and bisphenol S.

[0087] Examples of organic peroxide-based crosslinking agents include: tert-butyl hydroperoxide, p-menthol hydroperoxide, dicumyl peroxide, tert-butyl peroxide, 1,3-bis(tert-butylperoxyisopropyl)benzene, 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane, benzoyl peroxide, and tert-butyl peroxide.

[0088] Examples of aldehyde-based crosslinking agents include glyoxal, malondialdehyde, succinaldehyde, maleic anhydride, glutaraldehyde, formaldehyde, acetaldehyde, benzaldehyde, and 1,3,5-trioxane.

[0089] Examples of silane-based crosslinking agents include methyltrimethoxysilane, dimethyldimethoxysilane, vinyltrimethoxysilane, phenyltrimethoxysilane, methyltriethoxysilane, and other alkoxysilanes.

[0090] Among these, polyamine-based crosslinking agents and aldehyde-based crosslinking agents are preferred from the viewpoints of ease of addition (solvent solubility) and high reactivity (the carbon atoms adjacent to the electron-withdrawing atoms exist in a relatively large space (small steric hindrance)).

[0091] In the case where the near-infrared transmitting black particles of the present invention contain a copolymer having structural units derived from compounds having hydroxyl-containing aromatic rings and structural units derived from amino-containing compounds, the content ratio of the structural units derived from amino-containing compounds to the structural units derived from the structural units derived from the hydroxyl-containing aromatic rings (structural units derived from amino-containing compounds / structural units derived from the structural units derived from hydroxyl-containing aromatic rings) is preferably 0.1 or more and 50 or less, more preferably 0.5 or more and 30 or less, and even more preferably 0.8 or more and 10 or less. A content of 0.1 or more improves visible light blocking properties, and a content of 50 or less improves infrared transmittance.

[0092] Furthermore, the aforementioned compound having a hydroxyl-containing aromatic ring is preferably a combination of a compound having a hydroxyl-containing naphthalene ring and a compound having a hydroxyl-containing benzene ring. In this case, the ratio of structural units derived from the aforementioned compound having a hydroxyl-containing naphthalene ring to structural units derived from the aforementioned compound having a hydroxyl-containing benzene ring (structural units derived from the compound having a hydroxyl-containing benzene ring / structural units derived from the compound having a hydroxyl-containing naphthalene ring) is preferably 0.1 or more and 50 or less, more preferably 0.5 or more and 30 or less, and even more preferably 1 or more and 10 or less.

[0093] In the case where the near-infrared transmission black particles of the present invention contain a copolymer having structural units derived from a compound having a hydroxyl-containing aromatic ring and structural units derived from a crosslinking agent, the ratio of the structural units derived from the crosslinking agent to the structural units derived from the compound having a hydroxyl-containing aromatic ring (structural units derived from the crosslinking agent / structural units derived from the compound having a hydroxyl-containing aromatic ring) is preferably 0.3 or more and 10 or less, more preferably 0.5 or more and 5 or less, and even more preferably 0.5 or more and 2 or less.

[0094] Setting it to 10 or higher will not improve the effect of the present invention, and if it is below 0.3, it will become difficult to promote solidification.

[0095] The copolymer described above, having structural units derived from compounds containing hydroxyl aromatic rings and structural units derived from amino compounds, is obtained by polymerizing the aforementioned compounds containing hydroxyl aromatic rings and amino compounds. That is, the copolymer described above, having structural units derived from compounds containing hydroxyl aromatic rings and structural units derived from amino compounds, is a copolymer of a compound containing hydroxyl aromatic rings and an amino compound.

[0096] In the above polymerization reaction, the molar ratio (amino compound / compound having a hydroxyl-containing aromatic ring) of the above-mentioned compound having a hydroxyl-containing aromatic ring to the above-mentioned compound having a hydroxyl-containing aromatic ring is preferably 0.5 or more and 50 or less, more preferably 0.8 or more and 10 or less. A molar ratio of 0.5 or more can improve visible light blocking properties, and a molar ratio of 50 or less can improve infrared transmittance.

[0097] Furthermore, the aforementioned compound having a hydroxyl-containing aromatic ring is preferably a combination of a compound having a hydroxyl-containing naphthalene ring and a compound having a hydroxyl-containing benzene ring. In this case, the molar ratio of the aforementioned compound having a hydroxyl-containing naphthalene ring to the aforementioned compound having a hydroxyl-containing naphthalene ring (compound having a hydroxyl-containing benzene ring / compound having a hydroxyl-containing naphthalene ring) is preferably 0.5 or more and 50 or less, more preferably 1 or more and 10 or less.

[0098] In the above polymerization reaction, the molar ratio of the crosslinking agent to the compound having a hydroxyl-containing aromatic ring (crosslinking agent / compound having a hydroxyl-containing aromatic ring) is preferably 0.5 or more and 10 or less, more preferably 0.5 or more and 2 or less.

[0099] Setting it to 10 or higher will not improve the effect of the present invention, and if it is below 0.5, it will become difficult to promote solidification.

[0100] The polymerization temperature is preferably 0°C or higher, and more preferably 100°C or lower. By being within the above range, the average particle size of the aqueous dispersion can be made to a suitable degree.

[0101] It should be noted that, regarding the above polymerization reaction, the reaction is considered complete when the amount of monomer remaining in the reaction solution is confirmed and more than 70% by weight of the monomer has reacted and been polymerized.

[0102] In addition, the amount of the aforementioned residual monomers can be confirmed, for example, by heating the reaction solution to above the volatilization temperature of the aforementioned compound having a hydroxyl-containing aromatic ring and the aforementioned compound containing an amino group, and then drying it, measuring the amount of residual solid components; or by quantitative analysis based on gas chromatography.

[0103] In the above polymerization process, it is preferable to add additives.

[0104] Examples of such additives include: halogen compounds such as iodine, bromine, and chlorine; protic acids such as sulfuric acid, hydrochloric acid, nitric acid, perchloric acid, fluoroboric acid, and phosphonic acid; various salts of these protic acids; Lewis acids such as aluminum trichloride, ferric chloride, molybdenum chloride, antimony chloride, arsenic pentafluoride, and antimony pentafluoride; organic carboxylic acids such as acetic acid, trifluoroacetic acid, polyacrylic acid, formic acid, benzoic acid, and citric acid; various salts of these organic carboxylic acids; phenols such as phenol, nitrophenol, and cyanophenol; and these phenols Various salts of sulfosuccinic acids; sulfosuccinic acids such as di(2-ethylhexyl)sulfosuccinic acid and sulfosuccinic acid; salts of sulfosuccinic acids; high molecular weight acids such as polyacrylic acid; alkyl phosphates such as propyl phosphate, butyl phosphate, and hexyl phosphate; polyoxyethylene dodecyl ether phosphate and polyoxyethylene alkyl ether phosphate; various salts of alkyl phosphates and polyoxyethylene alkyl phosphates; sulfates such as lauryl sulfate, cetyl sulfate, stearyl sulfate, and lauryl ether sulfate; and various salts of these sulfates.

[0105] Regarding the molar ratio of the compound with a hydroxyl-containing aromatic ring to the compound with an amino group, the molar amount of the compound with the hydroxyl-containing aromatic ring is preferably 0.1 to 10 times the molar amount of the compound with an amino group, based on the proportioning ratio. By setting the molar ratio to 0.1 times or more, the compound with an amino group can be incorporated into the particles, thus demonstrating the effects of the present invention. Furthermore, by setting the molar ratio to 10 times or less, the effect of the compound with an amino group is improved, and the changes in light transmittance and barrier properties become more apparent, which is suitable.

[0106] As a method for producing the near-infrared transmission black particles of the present invention, examples include: a method of reacting a compound having a hydroxyl-containing aromatic ring, an amino-containing compound, and a crosslinking agent.

[0107] Specifically, examples include: preparing a solution containing a compound having an aromatic ring with a hydroxyl group, further adding a solution containing an amino group to react, and further adding a crosslinking agent solution.

[0108] The temperature at which the above reaction occurs is preferably above 0°C, and preferably below 100°C.

[0109] In addition, the reaction time is preferably 4 hours or more, and preferably 48 hours or less.

[0110] In the above method for producing near-infrared transmission black particles, a drying process can also be further performed.

[0111] The drying temperature in the above drying process is preferably above 80°C, and preferably below 200°C. Furthermore, the drying time is preferably above 1 hour, and preferably below 48 hours.

[0112] The near-infrared transmission black particles of the present invention can be used in coatings, black paints, black matrices for color filters, inks for infrared sensors, and other applications.

[0113] It should be noted that when using the near-infrared transmission black particles of the present invention to produce coatings, black paints, black matrices for color filters, inks for infrared sensors, etc., the transmittance is affected by the dispersion medium, dispersion method, resin binder used to form the coating, particle content, and coating thickness of the near-infrared transmission black particles. By adjusting these parameters, the dispersion medium can be selected from hydrophilic to hydrophobic solvents. Furthermore, the particle content can be adjusted to be 100 parts by weight or less relative to the resin binder, and the coating thickness can be adjusted to 30 μm or less.

[0114] As a method for forming the aforementioned black matrix, firstly, the near-infrared transmission black particles of the present invention, a curing compound, and further, as needed, a curing agent, a solvent, etc., are mixed using a mixer to prepare a composition containing near-infrared transmission black particles.

[0115] Next, the above composition is coated onto the substrate and dried to form a coating film.

[0116] The resulting coating is partially exposed by irradiating it with active energy rays such as ultraviolet light or excimer laser through a negative mask, thereby forming a black matrix with a prescribed pattern shape.

[0117] Furthermore, by performing the aforementioned method of forming a black matrix on a photosensitive resin composition in which red pigment is dispersed, a photosensitive resin composition in which green pigment is dispersed, and a photosensitive resin composition in which blue pigment is dispersed, pixel patterns of various colors can be formed, thereby enabling the formation of a color filter.

[0118] The above-mentioned photosensitive resin composition containing red pigment, the above-mentioned photosensitive resin composition containing green pigment, and the above-mentioned photosensitive resin composition containing blue pigment can use photosensitive resin compositions that have been known all along.

[0119] It should be noted that the above-mentioned color filter can also be manufactured by the following method: spraying red, green and blue inks from inkjet nozzles into the areas divided by the above-mentioned black matrix, and using heat or light to solidify the accumulated ink.

[0120] The aforementioned color filter is suitable for use as a component in display devices such as liquid crystal displays and organic electroluminescent displays.

[0121] Invention Effects

[0122] According to the present invention, near-infrared transmissive black particles with high transmittance in the near-infrared region and low transmittance in the visible light region can be provided. It should be noted that the transmittance in the near-infrared region (wavelengths above 1100 nm) at longer wavelengths can also be high.

[0123] Furthermore, since the near-infrared transmission black particles of the present invention do not use carbon-based or metal-based materials, they can achieve high electrical insulation.

[0124] Furthermore, when using the near-infrared transmission black particles of the present invention, it is not necessary to increase the thickness of the formed coating film or increase the amount of particles added to the required amount, thus increasing the freedom of coating design.

[0125] Furthermore, the near-infrared transmission black particles of the present invention can be suitable for use in black coatings, films, black matrices for color filters, inks for infrared sensors, and other applications. Attached Figure Description

[0126] Figure 1 The graphs (horizontal axis: wavelength, vertical axis: transmittance) are obtained when the total transmittance of the coatings obtained in Examples 1-5 and Comparative Examples 1 and 2 is measured. Detailed Implementation

[0127] The following embodiments further illustrate the present invention in detail, but the present invention is not limited to these embodiments.

[0128] (Example 1)

[0129] 12 g (75 mmol) of 1,5-dihydroxynaphthalene (manufactured by Tokyo Chemical Industry Co., Ltd.) and 37.4 g (225 mmol) of tert-butylcatechol (manufactured by Tokyo Chemical Industry Co., Ltd.) were added to 3.5 L of 2-propanol and stirred to obtain a mixed solution of 1,5-dihydroxynaphthalene and tert-butylcatechol.

[0130] In addition, 55.4 g (450 mmol) of p-anisidine (manufactured by Tokyo Chemical Industry Co., Ltd.) was dissolved in 3.5 L of water to obtain an aqueous solution.

[0131] The obtained aqueous solution of p-anisidine was added dropwise to a mixed solution of 1,5-dihydroxynaphthalene and tert-butylcatechol for mixing.

[0132] The resulting mixture was stirred at room temperature (25°C) for 8 hours, then heated to 60°C and stirred for another 12 hours. After cooling to room temperature, 210 g (150 mmol) of a 10% aqueous solution of hexamethylenetetramine (manufactured by Fujifilm and Koichi Chemical Co., Ltd.) was added. The mixture was stirred at room temperature (25°C) for 8 hours, then heated to 80°C and stirred for another 12 hours. After cooling to room temperature, a particulate dispersion was obtained.

[0133] The obtained particle dispersion was filtered through a 0.1 μm membrane filter and then dried under vacuum at 110 °C for 3 hours to obtain black powder particles.

[0134] It should be noted that since the solid content (by weight after drying) on ​​the filtrate side is almost non-existent (equivalent to less than 0.1% of the total solid content), it can be confirmed that the added ingredients are almost entirely contained within the black powder particles.

[0135] Cyclohexanone was added to obtain a black particle dispersion (cyclohexanone concentration 90 wt%) by stirring, with the resulting black powder particles having a concentration of 1 wt% and polyvinyl butyral (S-LECBH-S, manufactured by Sekisui Chemicals Co., Ltd.) having a concentration of 9 wt%.

[0136] The obtained black particle dispersion was coated onto a glass slide using a coating machine and dried at 90°C, thereby forming a coating film on the glass slide (the coating film thickness after drying was 30 μm).

[0137] (Example 2)

[0138] The same procedure as in Example 1 was followed to obtain black powder particles and coatings, except that 24.8 g (225 mmol) of hydroquinone (manufactured by Fujifilm and Koichi Chemical Co., Ltd.) was used instead of tert-butylcatechol.

[0139] (Example 3)

[0140] Black powder particles and coatings were obtained by operating in the same manner as in Example 1, except that 10.8 g (75 mmol) of 1-naphthol (manufactured by Fujifilm and Koichi Chemical Co., Ltd.) was used instead of 1,5-dihydroxynaphthol.

[0141] (Example 4)

[0142] Black powder particles and coatings were obtained by operating in the same manner as in Example 1, except that 41.9 g (450 mmol) of aniline (manufactured by Fujifilm and Koichi Chemical Co., Ltd.) was used instead of anisidine.

[0143] (Example 5)

[0144] Using 43.3 g (300 mmol) of 1-naphthol (manufactured by Fujifilm and Koichi Chemical Co., Ltd.) instead of 1,5-dihydroxynaphthalene and tert-butylcatechol, using 12.2 g (90 mmol) of N,N-dimethyl-1,4-phenylenediamine (manufactured by Tokyo Chemical Industry Co., Ltd.) instead of p-anisidine, and further using 18.6 g (205 mmol) of 1,3,5-trioxane (manufactured by Tokyo Chemical Industry Co., Ltd.) instead of the hexamethylenetetramine aqueous solution, the same procedure as in Example 1 was followed to obtain black powder particles and coating film.

[0145] (Examples 6-11)

[0146] Except for the compounds and crosslinking agents shown in Table 1, black powder particles and coatings were obtained by operating in the same manner as in Example 1.

[0147] (Comparative Example 1)

[0148] Black powder particles and coatings were obtained by operating in the same manner as in Example 1, except that 37.4 g (225 mmol) of tert-butylcatechol (manufactured by Tokyo Chemical Industry Co., Ltd.) was not added and the aqueous solution of p-anisidine was not mixed.

[0149] (Comparative Example 2)

[0150] Except for the absence of 12 g (75 mmol) of 1,5-dihydroxynaphthalene (manufactured by Tokyo Chemical Industry Co., Ltd.), the same procedure as in Example 4 was followed to obtain black powder particles and coating film.

[0151] (Comparative Example 3)

[0152] The procedure was performed in the same manner as in Example 1, except that 12 g (75 mmol) of 1,5-dihydroxynaphthalene (manufactured by Tokyo Chemical Industry Co., Ltd.) and 37.4 g (225 mmol) of tert-butylcatechol (manufactured by Tokyo Chemical Industry Co., Ltd.) were not added, but no black powder particles or coating were obtained.

[0153] (evaluate)

[0154] The black powder particles and coatings obtained in the Examples and Comparative Examples were evaluated as follows. The results are shown in Table 1.

[0155] (1) Total transmittance

[0156] For the obtained coating, the transmittance in the wavelength range of 400–1200 nm was measured using a spectrophotometer with an integrating sphere (Hitachi, U-4100 model). It should be noted that during the measurement, a reflector was mounted on the opposite side of the light incident side to determine the total transmittance.

[0157] Next, the transmittance T at a wavelength of 600 nm was determined. 600 (%) and transmittance T at wavelength 900 nm 900 (%), calculate T 900 -T 600 Additionally, regarding the transmittance T at wavelengths of 650, 700, 750, 800, and 850 nm... 650 T 700 T 750 T 800 T 850 (%) is also shown in Table 1.

[0158] In addition, T was continuously measured. 1100 (Transmittance at 1100nm wavelength) ~ T 2000 The transmittance (transmittance at a wavelength of 2000 nm) will be the median value (T). 1550Cases with a transmittance of 90% or higher are marked as "○", while cases with a transmittance of less than 90% are marked as "×". It should be noted that T... 1550 It represents the transmittance at longer wavelengths in the near-infrared region.

[0159] It should be noted that, for Examples 1-5 and Comparative Examples 1 and 2, the transmittance graphs relative to wavelength are presented as follows: Figure 1 .

[0160] (2) Diffusion transmittance

[0161] Remove the reflector on the opposite side of the light incident side of the spectrophotometer with integrating sphere (Hitachi, U-4100 model) and set it up so that parallel light rays do not remain in the integrating sphere and only diffuse light remains in the integrating sphere. Measure the diffuse transmittance in the wavelength range of 400 to 1200 nm for the same coating used in the total transmittance measurement (1).

[0162] Next, the diffusion transmittance Td at a wavelength of 600 nm was determined. 600 (%), diffusion transmittance Td at wavelength 900 nm 900 (%) and diffusion transmittance Td at wavelength 1100 nm 1100 (%).

[0163] [Table 1]

[0164]

[0165] Industrial availability

[0166] According to the present invention, it is possible to provide near-infrared transmissive black particles with high transmittance in the near-infrared region and low transmittance in the visible light region.

Claims

1. A near-infrared transmitting black particle comprising: a copolymer having structural units derived from a compound having a hydroxyl-containing aromatic ring, structural units derived from an amino-containing compound, and structural units derived from a crosslinking agent. The copolymer is prepared by mixing and reacting the compound having a hydroxyl-containing aromatic ring, the amino-containing compound, and the crosslinking agent. In the reaction, the molar ratio of the amino-containing compound to the compound having a hydroxyl-containing aromatic ring is 0.5 or more and 50 or less, and the molar ratio of the crosslinking agent to the compound having a hydroxyl-containing aromatic ring is 0.5 or more and 10 or less. The compound having a hydroxyl-containing aromatic ring is a combination of a compound having a hydroxyl-containing naphthalene ring and a compound having a hydroxyl-containing benzene ring. The compound having a hydroxyl-containing naphthalene ring is selected from 1-naphthol and dihydroxynaphthalene. In the dihydroxynaphthalene, when the hydroxyl group is substituted at position 1, the positions 2 and / or 4 are composed of unsubstituted hydrogen atoms; when the hydroxyl group is substituted at position 2, the positions 1 and / or 3 are composed of unsubstituted hydrogen atoms. The compound having a hydroxyl-containing benzene ring is selected from tert-butylphenol, tert-butylcatechol, hydroquinone, pyrogallol, and 4-ethylresorcinol. The amino-containing compound has the structure of the following formula (6), The crosslinking agent is selected from polyamine-based crosslinking agents and aldehyde-based crosslinking agents. The transmittance T of the near-infrared transmissive black particles at a wavelength of 600 nm was measured using a spectrophotometer. 600 and the transmittance T at a wavelength of 900 nm 900 The transmittance T satisfies the following relationship (1). 600 and transmittance T 900 In percentage terms, The diffusion transmittance Td at a wavelength of 900 nm was measured using a spectrophotometer. 900 Calculated as a percentage, less than 3%, T 900 -T 600 ≥60 (1), In equation (6), R X The symbols -OR or -NR'R'' represent hydrogen, and R, R', and R'' represent alkyl groups with 20 or fewer carbon atoms.

2. A near-infrared transmitting black particle comprising: a copolymer having structural units derived from compounds containing hydroxyl aromatic rings, structural units derived from amino-containing compounds, and structural units derived from crosslinking agents. The copolymer is prepared by mixing and reacting the compound having a hydroxyl-containing aromatic ring, the amino-containing compound, and the crosslinking agent. In the reaction, the molar ratio of the amino-containing compound to the compound having a hydroxyl-containing aromatic ring is 0.5 or more and 50 or less, and the molar ratio of the crosslinking agent to the compound having a hydroxyl-containing aromatic ring is 0.5 or more and 10 or less. The compound having a hydroxyl-containing aromatic ring is a combination of a compound having a hydroxyl-containing naphthalene ring and a compound having a hydroxyl-containing benzene ring. The compound having a hydroxyl-containing naphthalene ring is selected from 1-naphthol and dihydroxynaphthalene. In the dihydroxynaphthalene, when the hydroxyl group is substituted at position 1, the positions 2 and / or 4 are composed of unsubstituted hydrogen atoms; when the hydroxyl group is substituted at position 2, the positions 1 and / or 3 are composed of unsubstituted hydrogen atoms. The compound having a hydroxyl-containing benzene ring is selected from tert-butylphenol, tert-butylcatechol, hydroquinone, pyrogallol, and 4-ethylresorcinol. The amino-containing compound has the structure of the following formula (6), The crosslinking agent is selected from polyamine-based crosslinking agents and aldehyde-based crosslinking agents. The transmittance T of the near-infrared transmissive black particles at a wavelength of 600 nm was measured using a spectrophotometer. 600 and the transmittance T at a wavelength of 900 nm 900 The transmittance T satisfies the following relationship (1). 600 and transmittance T 900 In percentage terms, The diffusion transmittance Td at a wavelength of 1100 nm was measured using a spectrophotometer. 1100 Calculated as a percentage, less than 3%, T 900 -T 600 ≥60 (1) In equation (6), R X The symbols -OR or -NR'R'' represent hydrogen, and R, R', and R'' represent alkyl groups with 20 or fewer carbon atoms.

3. The near-infrared transmission black particles according to claim 1 or 2, wherein, T 600 Less than 10%, and T 900 Greater than 80%.

4. The near-infrared transmission black particles according to claim 2, wherein, The diffusion transmittance Td at a wavelength of 900 nm was measured using a spectrophotometer. 900 It is expressed as less than 10% (in percentage terms).

5. The near-infrared transmission black particles according to claim 1, wherein, The diffusion transmittance Td at a wavelength of 1100 nm was measured using a spectrophotometer. 1100 It is expressed as less than 10% (in percentage terms).

6. The near-infrared transmitting black particles according to claim 1 or 2, wherein, The copolymer having structural units derived from compounds with hydroxyl-containing aromatic rings, structural units derived from amino-containing compounds, and structural units derived from crosslinking agents contains auxochromes.

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