Black pigment dispersion

Abstract

The present invention provides a black pigment dispersion. In the preparation of a pigment dispersion liquid containing perylene black, the dispersion liquid is prevented from gelling or the viscosity of the dispersion liquid is prevented from changing during storage, and the dispersibility is improved. The black pigment dispersion is used with perylene black, any one of the derivatives shown by Chemical Formulas 1 to 3, and a dispersant that is a copolymer composed of a monomer A having the structure of Chemical Formula 4, a monomer B having a basic functional group, and a monomer C capable of polymerizing with the monomer A and the monomer B, the monomer B is a monomer having a nitrogen-containing aromatic heterocyclic group as a basic functional group and / or a monomer having the structure of Chemical Formula 5, and the amine value of the dispersant is 120 mgKOH / g to 200 mgKOH / g. The content of perylene black is 5 mass% to 25 mass%. The average particle diameter of perylene black is preferably adjusted to 200 nm or less.

Description

Technical Field

[0001] This invention relates to a black pigment dispersion containing perylene black with excellent dispersibility. Background Technology

[0002] Liquid crystal display devices have a liquid crystal cell structure in which liquid crystal material is filled between two opposing glass substrates, each equipped with a transparent electrode. Furthermore, to maintain a uniform gap between the substrates and provide a good image, pillar spacers are inserted between the two glass substrates. Conventionally, beaded glass or similar material has been used as such pillar spacers. However, using beaded spacers has revealed the following problems: light leakage occurs because the beads are randomly dispersed in the gap; sometimes the gap distance deviation becomes large; and it is difficult to control mechanical properties such as elasticity. In addition, based on the market demand for higher image quality in liquid crystal display devices in recent years, more precise gap control is required.

[0003] As an improvement measure, a black pillar separator using a black photosensitive resin composition was proposed instead of a bead separator (Patent Documents 1 and 2). Using a black pillar separator allows for the formation of pillar separators at desired locations with smaller deviations in gap distance, making it easier to control properties such as photopolymerizable components. Therefore, it is believed that more precise gap control is possible compared to the case of bead separators. Furthermore, by containing a black colorant in the pillar separator to block visible light (wavelengths of 380 nm to 750 nm), improvements in contrast and color rendering are expected. Perylene black is exemplified as such a black colorant in Patent Documents 1 and 2. Additionally, as an example of perylene black, Patent Document 3 discloses a pigment with a specific structure.

[0004] Patent document 4 discloses a black pigment composition that can absorb light in the visible light region without using black carbon and can suppress the absorption of infrared and ultraviolet rays. As a black pigment composition with good solvent resistance, it contains perylene black with a specific structure, at least two colored organic pigments other than perylene black, a dispersant and a solvent.

[0005] Patent Document 5 discloses a coloring composition for color filters, characterized in that, as a coloring composition for color filters with excellent dispersibility, good flowability, stability, and excellent developability, it contains a colorant, a resin-type dispersant, and a solvent. The colorant contains a pigment with an average primary particle size of 20 nm to 50 nm and a pigment particle aspect ratio of 1:1 to 1:3.5. The resin-type dispersant is an AB block copolymer or a BAB block copolymer composed of a solvent-friendly A block and a B block containing a nitrogen-containing functional group, and contains an acrylic block copolymer with an amine value of 10 mg KOH / g to 99 mg KOH / g converted from effective solid content.

[0006] Existing technical documents

[0007] Patent documents

[0008] Patent Document 1: Japanese Patent Application Publication No. 2015-191234

[0009] Patent Document 2: Japanese Patent Application Publication No. 2007-71994

[0010] Patent Document 3: Japanese Patent No. 4980727

[0011] Patent Document 4: Japanese Patent Application Publication No. 2017-226821

[0012] Patent Document 5: Japanese Patent Application Publication No. 2012-212054 Summary of the Invention

[0013] Perylene black has excellent light-shielding properties, therefore, black matrices formed using black coloring compositions containing perylene black exhibit excellent display contrast in color liquid crystal displays. Furthermore, due to its low dielectric constant, it is less prone to defects caused by the electrical properties of the black matrix, such as liquid crystal alignment disorder and conduction between electrodes formed on thin-film transistor (TFT) substrates. Additionally, its excellent transmittance in the near-infrared region allows for mask alignment operations, making it suitable for driving substrates in TFT-based color liquid crystal displays.

[0014] A drawback of perylene black is its poor dispersibility. As disclosed in Patent Document 5, dispersants are used to improve the dispersibility in black coloring compositions (black pigment dispersions). However, even if the dispersibility during the preparation of black pigment dispersions can be improved, the dispersibility will decrease during storage, sometimes resulting in increased particle size or gelation. In addition, there are also cases where the viscosity of the dispersion increases, etc., requiring further improvement in the dispersibility of perylene black.

[0015] The purpose of this invention is to provide a black pigment dispersion containing perylene black as a black pigment, which not only exhibits excellent dispersibility during preparation but also during storage.

[0016] In order to solve the above-mentioned problems, the inventors conducted repeated in-depth research and found that when perylene black is used as a black pigment in the pigment dispersion, the dispersibility of perylene black can be improved by using it in combination with specific derivatives and dispersants, thus completing the present invention.

[0017] Specifically, this invention relates to a black pigment dispersion comprising at least a black pigment, a derivative, a dispersant, and a solvent.

[0018] The aforementioned black pigment is perylene black.

[0019] The aforementioned derivatives are any one of the derivatives represented by chemical formula 1, chemical formula 2, or chemical formula 3.

[0020] The dispersant described above is a copolymer composed of monomer A having the chemical formula 4, monomer B having a basic functional group, and monomer C capable of polymerizing with A and B.

[0021] The monomer B mentioned above is a monomer having a nitrogen-containing aromatic heterocyclic group as a basic functional group and / or a monomer having the structure of chemical formula 5.

[0022] The amine value of the above dispersant is 120 mg KOH / g to 200 mg KOH / g.

[0023]

[0024] (In chemical formula 2, n = 1 to 2)

[0025]

[0026] CH2=C(R1)COO(CH2CH2O) n R2··· Chemical Formula 4

[0027] (In chemical formula 4, R1 is hydrogen or methyl, R2 is an alkyl group with 1 to 8 carbon atoms, and n = 4 to 23)

[0028] CH2=C(R3)-AB-NR4R5···Chemical Formula 5

[0029] (In chemical formula 5, R3 is hydrogen or methyl, A is -COO- or -CONH-, B is an alkylene group with 1 to 6 carbon atoms, and R4 and R5 are independently hydrogen or alkyl groups with 1 to 3 carbon atoms. R4 and R5 can bond together with the adjacent nitrogen atom to form a 5 to 7-membered heterocycle.)

[0030] The black pigment dispersion of the present invention, by using any of the derivatives shown in chemical formulas 1 to 3 and a specific polymeric dispersant, exhibits superior dispersibility and stability of perylene black compared to existing black pigment dispersions containing perylene black.

[0031] The perylene black described above is preferably the perylene black shown in chemical formula 6 and / or chemical formula 7.

[0032]

[0033]

[0034] The average particle size (cumulative average particle size) of the aforementioned perylene black is preferably 200 nm or less, more preferably 170 nm or less. This is because if the average particle size is 200 nm or less, the perylene black exhibits excellent dispersibility. Even if the average particle size is 170 nm or less, it needs to prevent aggregation over time (dispersion stability). From the viewpoints of dispersion stability and light-shielding properties, the average particle size is preferably 50 nm or more.

[0035] The content of the aforementioned black pigment is preferably 5% to 25% of the total mass of the black pigment dispersion, more preferably 8% to 15% by mass. When it is less than 5% by mass, the pigment concentration is low, so the coloring may be insufficient. When it exceeds 25% by mass, the viscosity becomes high, which can easily lead to a decrease in operability.

[0036] From the viewpoint of dispersion stability, the content of the above-mentioned derivatives relative to the pigment mass (the mass of pigment contained in the black pigment dispersion) is preferably 5% to 50% by mass, more preferably 10% to 40% by mass.

[0037] From the viewpoint of optical properties such as dispersion stability, OD value, and color purity, the content of the above-mentioned dispersant relative to the total mass of the pigment and derivatives (the total mass of the pigment and derivatives contained in the black pigment dispersion) is preferably 5% to 80% by mass, more preferably 20% to 60% by mass. The optimal content of the derivatives and dispersant can be appropriately adjusted according to the type and combination of the pigment, derivatives, and dispersant used.

[0038] The black pigment dispersion of the present invention may further contain acrylic resin, polyester resin, or resin having a cardo structure, which have acidic groups. By containing such resins, improved developability and adhesion can be obtained.

[0039] The black pigment dispersion of the present invention may further contain auxiliary components such as viscosity modifiers.

[0040] For the black pigment dispersion of the present invention, perylene black has excellent dispersibility, does not gel during preparation, and its average particle size and viscosity do not easily change during storage. Detailed Implementation

[0041] The embodiments of the present invention will be described below.

[0042] (Black pigment)

[0043] As perylene black, known black organic pigments with a perylene structure can be used, such as CI Pigment Black 31, CI Pigment Black 32, and perylene black represented by chemical formula 6 and / or chemical formula 7. One or more such perylene black pigments can be used. Alternatively, commercially available perylene black pigments can be used, such as Lumogen (registered trademark) Black FK4280 (BASF), Paliogen (registered trademark) Black S0084 (BASF / CI Pigment Black 31), etc. Lumogen (registered trademark) Black FK4280 has a structure of chemical formula 6 or chemical formula 7.

[0044] (derivative)

[0045] The derivatives used in this invention are any one of the derivatives shown in Chemical Formula 1, Chemical Formula 2, or Chemical Formula 3. Only one or more of these derivatives may be used. These derivatives can be synthesized and used according to conventional methods. The derivatives shown in Chemical Formulas 1 to 3 all have a sulfonic acid group, but are not metal salts; instead, they are free acids.

[0046] (Dispersant)

[0047] As monomer A, monomers belonging to the Light Acrylate series manufactured by Kyoeisha Chemical Co., Ltd. and the NEW FRONTIER (registered trademark) series manufactured by Daiichi Kogyo Pharmaceutical Co., Ltd. can be used.

[0048] Monomer B is a monomer having a nitrogen-containing aromatic heterocyclic group as a basic functional group and / or a monomer having the structure of Formula 5. As a monomer having a nitrogen-containing aromatic heterocyclic group as a basic functional group, 4-vinylpyridine, 2-vinylpyridine, etc., can be used. As a monomer having the structure of Formula 5, monomers belonging to the Light Ester series manufactured by Kyoei Chemical Co., Ltd., the Kohshylmer (registered trademark) series manufactured by KJ Chemicals Co., Ltd., etc., can be used.

[0049] From the viewpoint of not affecting the dispersibility of the pigment, monomer C is preferably a nonionic monomer. As a nonionic monomer, alkyl methacrylates such as methyl methacrylate and butyl methacrylate are preferred.

[0050] The content of monomers A to C in the dispersant can be appropriately changed in such a way that monomer A is 10 to 60 parts by mass, monomer B is 10 to 50 parts by mass, monomer C is 20 to 60 parts by mass, and the total is 100 parts by mass.

[0051] The acid value and amine value of the dispersant used as a copolymer of monomers A to C are determined by the functional groups contained in the copolymer and their content. The acid value (acid value when converting to solids content) can be determined, for example, according to DIN EN ISO 2114, and the amine value (amine value when converting to solids content) can be determined, for example, according to DIN 16945. The acid value of the dispersant is preferably 1 mg KOH / g or less. The amine value of the dispersant is preferably 120 mg KOH / g to 200 mg KOH / g, more preferably 150 mg KOH / g to 180 mg KOH / g.

[0052] (solvent)

[0053] As solvents, various organic solvents can be used, such as aromatic, ketone, ester, diol ether, alcohol, and aliphatic solvents. There can be only one organic solvent, or a combination of two or more.

[0054] As aromatic organic solvents, examples include aromatic hydrocarbons such as toluene, xylene, and ethylbenzene.

[0055] Examples of organic solvents that can be used as ketones include methyl ethyl ketone, methyl isobutyl ketone, diisobutyl ketone, acetylacetone, isophorone, acetophenone, and cyclohexanone.

[0056] Examples of ester-based organic solvents include, for example, ethyl acetate, n-butyl acetate, isobutyl acetate, isopropyl acetate, methyl propionate, 3-methoxybutyl acetate, ethylene glycol acetate, propylene glycol monomethyl ether acetate (PMA), propylene glycol monoethyl ether acetate, 3-methyl-3-methoxybutyl acetate, methyl monochloroacetate, ethyl monochloroacetate, butyl monochloroacetate, methyl acetoacetate, ethyl acetoacetate, butyl carbitol acetate, butyl lactate, ethyl-3-ethoxypropionate, ethylene glycol monobutyl ether acetate, ethylene glycol monomethyl ether acetate, propyl acetate, and 1,3-butanediol diacetate.

[0057] Examples of water-soluble diol ethers that can be used as organic solvents for diol ether systems include ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol mono-n-propyl ether, ethylene glycol monoisopropyl ether, diethylene glycol monoisopropyl ether, ethylene glycol mono-n-butyl ether, diethylene glycol mono-n-butyl ether, triethylene glycol mono-n-butyl ether, ethylene glycol mono-tert-butyl ether, diethylene glycol mono-tert-butyl ether, 1-methyl-1-methoxybutanol, propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol mono-tert-butyl ether, propylene glycol mono-n-propyl ether, propylene glycol monoisopropyl ether, dipropylene glycol monomethyl ether, dipropylene glycol monoethyl ether, dipropylene glycol mono-n-propyl ether, dipropylene glycol monoisopropyl ether, propylene glycol mono-n-butyl ether, and dipropylene glycol mono-n-butyl ether.

[0058] Non-water-soluble diol ethers such as ethylene glycol monohexyl ether, ethylene glycol-2-ethylhexyl ether, ethylene glycol phenyl ether, diethylene glycol n-hexyl ether, diethylene glycol-2-ethylhexyl ether, propylene glycol monobutyl ether, dipropylene glycol monobutyl ether, dipropylene glycol propyl ether, and propylene glycol methyl ether propionate.

[0059] Examples of organic solvents that are alcohols include alkyl alcohols with 1 to 4 carbon atoms, such as ethanol, methanol, butanol, propanol, and isopropanol.

[0060] Ethylene glycol, propylene glycol, diethylene glycol, pentanediol, trimethylene glycol, 2-butene-1,4-diol, 2-ethyl-1,3-hexanediol, 2-methyl-2,4-pentanediol, tripropylene glycol, polyethylene glycol with a molecular weight of less than 2000, 1,3-propanediol, isopropylene glycol, isobutylene glycol, 1,4-butanediol, 1,3-butanediol, 1,5-pentanediol, 1,6-hexanediol, glycerol, erythritol, pentaerythritol, etc.

[0061] Examples of aliphatic organic solvents include aliphatic hydrocarbons such as n-pentane, n-hexane, and n-heptane.

[0062] From the viewpoint of ease of operation, the solvent content is preferably adjusted so that the concentration of solid components, including pigments, is 6 to 40% by weight.

[0063] <Example of manufacturing a black pigment composition>

[0064] Black pigment dispersions are manufactured using the following raw materials and manufacturing methods.

[0065] (Black pigment)

[0066] As for Perylene Black, Lumogen (registered trademark) Black FK4280 (BASF) and Paliogen (registered trademark) Black S0084 (BASF) are used.

[0067] (derivative)

[0068] As derivatives, derivatives 1 to 8 and Solsperse (registered trademark) 5000 (Lubrizol Corporation, Japan / containing sulfonic acid group (ammonium salt)) are used.

[0069] (Method for manufacturing derivative 1)

[0070] 20 parts by weight of CI Pigment Yellow 138 (BASF, Paliotol (registered trademark) Gelb K0961HD) and 300 parts by weight of 98% concentrated sulfuric acid were placed in a 500 mL detachable flask and reacted at 120°C for 5 hours to obtain a sulfonated phthalimide quinophthalone compound. The reaction mixture was stirred while being added to 3000 parts by weight of water to precipitate the sulfonated phthalimide quinophthalone compound. After stirring for 30 minutes, the mixture was filtered and washed with water three times. The resulting wet filter cake was washed with 300 parts by weight of 1% dilute sulfuric acid, filtered, and washed with water. It was dried in a hot air dryer to obtain 54 parts by weight of derivative 1, as shown in Formula 1.

[0071] The obtained derivative 1 was analyzed by mass spectrometry using a liquid chromatography-mass spectrometry (LC / MS) instrument manufactured by Hewlett-Packard, and the result showed that m / z = 773 [MH]-.

[0072] (Method for manufacturing derivative 2)

[0073] Derivative 2, as shown in chemical formula 8, was obtained using conventional methods.

[0074]

[0075] (Method for manufacturing derivative 3)

[0076] Derivative 3, as shown in chemical formula 9, was obtained using conventional methods.

[0077]

[0078] (Method for manufacturing derivative 4)

[0079] Derivative 4, represented by chemical formula 10, was obtained using conventional methods.

[0080]

[0081] (Method for manufacturing derivative 5)

[0082] Derivative 5, represented by chemical formula 11, was obtained using conventional methods.

[0083]

[0084] (Manufacturing method of derivative 6)

[0085] 15 parts by mass of CI Pigment Orange 43, 1.6 parts by mass of paraformaldehyde, and 8.4 parts by mass of 4-aminophthalimide were added to 200 parts by mass of 98% concentrated sulfuric acid, and the mixture was reacted at 85°C for 5 hours. Next, the solution was added to 1 L of ice water, filtered, and washed with water to obtain 19.5 parts by mass of (4-aminophthalimide methyl)-CI Pigment Orange 43 containing one 4-aminophthalimide methyl group.

[0086] Next, 10 parts by mass of (4-aminophthalimide methyl)-CI pigment orange 43 were dispersed in 100 parts by mass of water, and 3.6 parts by mass of cyanuric chloride (the amount that reacts with one amino group) were added. The mixture was reacted at 30°C for 1 hour. Next, 3.4 parts by mass of o-aminobenzenesulfonic acid (2-aminobenzenesulfonic acid) were added, and the mixture was reacted at 80°C for 2 hours. The remaining 1 Cl group was hydrolyzed to obtain 15.2 parts by mass of derivative 6 as shown in formula 2.

[0087] Using an AXIMA CFR plus matrix-assisted laser desorption / ionization-time-of-flight mass spectrometer (Shimadzu Corporation), the molecular ion peak of derivative 6 was determined in positive ion mode using α-cyano-4-hydroxycinnamic acid (CHCA) as the matrix. The peak was confirmed at m / z = 854. This ion peak corresponds to the compound with n = 1.

[0088] (Manufacturing method of derivative 7)

[0089] Add 18.4 parts by mass of cyanuric chloride and 17.3 parts by mass of o-aminobenzenesulfonic acid (reacting with one chlorine atom of cyanuric chloride) to 100 parts by mass of water, and react at 10°C for 1 hour. Add 16.6 parts by mass of 3-amino-4-methoxybenzamide (reacting with two chlorine atoms of the reactant) to the resulting reactant, and react at 85°C for 1 hour. Filter the reactant, wash the resulting residue with water, and let it stand overnight in a constant temperature bath at 100°C to dry, yielding 32.5 parts by mass of derivative 3 as shown in formula 3.

[0090] Using an AXIMA CFR plus matrix-assisted laser desorption / ionization-time-of-flight mass spectrometer (manufactured by Shimadzu Corporation), the molecular ion peak of derivative 7 was determined in positive ion mode using α-cyano-4-hydroxycinnamic acid (CHCA) as the matrix. The peak was confirmed at m / z = 582.

[0091] (Manufacturing method of derivative 8)

[0092] Derivative 8, an aluminum salt of derivative 1, was obtained by the method described in paragraph

[0148] of Japanese Patent Application Publication No. 2012-212054.

[0093] (solvent)

[0094] Propylene glycol monomethyl ether acetate (PMA) was used as the solvent.

[0095] (Dispersant)

[0096] Dispersants I through IV, described later, were used as dispersants. The amine value, Mp (peak molecular weight), Mw / Mn (weight-average molecular weight to number-average molecular weight ratio), NV (solids or non-volatile components), and monomer composition (numbers indicating the mass ratio of monomers) of each dispersant are shown in Table 1. The structures represented by the abbreviations in the monomer composition column of Table 1 are shown in Table 2.

[0097] [Table 1]

[0098] dispersant Amine value Mp Mw / Mn NV (%) Composition (mass ratio) Dispersant I 168.6 11500 1.24 40.5 MMA / BMA / MPEG9MA / 4VPy=45.6 / 0.1 / 22.6 / 31.7 Dispersant II 165.7 11200 1.19 40.8 MMA / BMA / MPEG9MA / DM=35.1 / 0.1 / 17.4 / 47.4 Dispersant III 159.7 5800 1.22 39.0 MMA / BMA / MPEG9MA / DMAPAA=35.3 / 0.1 / 17.5 / 47.1 Dispersant IV 57.3 11610 1.17 40.3 MMA / BMA / MPEG9MA / DE=53.1 / 0.1 / 26.2 / 20.6

[0099] [Table 2]

[0100]

[0101] (Method for manufacturing dispersant I)

[0102] In a 2L stainless steel detachable flask, 287.3 parts by weight of methyl methacrylate (MMA), 0.6 parts by weight of butyl methacrylate (BMA), 142.4 parts by weight of methoxy polyethylene glycol methacrylate (MPEG9MA), 15 parts by weight of N-(tert-butyl)-N-(1-diethylphosphono-2,2-dimethylpropyl)-O-(2-carboxypropyl-2-yl)hydroxylamine (manufactured by Arkema, product name BlocBuilder MA), 436 parts by weight of propylene glycol monomethyl ether acetate (PMA), and 218 parts by weight of propylene glycol monomethyl ether (PM) were added. The mixture was stirred while being bubbled with nitrogen, and the flask was heated to 125°C using an oil bath. The reaction was carried out for 4 hours.

[0103] Next, 199.7 parts by mass of 4-vinylpyridine (4VPy), 196 parts by mass of PMA, and 98 parts by mass of PM were added to a flask. The mixture was then stirred while being bubbled with nitrogen and reacted at 125°C for 4 hours.

[0104] The solids content of the reaction mixture was 40.5% by weight. The obtained block copolymer was determined by GPC (gel permeation chromatography), and the peak molecular weight was 11500, with a Mw / Mn ratio of 1.24. The amine value (solids content) was 168.6 mg KOH / g.

[0105] The resulting block copolymer (dispersant I) comprises: blocks having constituent units from MMA (monomer C), BMA (monomer C), and MPEG9MA (monomer A); and blocks having constituent units from 4VPy (monomer B) as basic groups. That is, dispersant I is a linear block polymer having blocks at one end composed of units containing basic groups. In terms of monomer composition, dispersant I does not possess acidic groups. The mass ratio of each constituent unit of dispersant I (MMA / BMA / MPEG9MA / 4VPy) is 45.6 / 0.1 / 22.6 / 31.7.

[0106] (Preparation of Dispersant II)

[0107] DM is used instead of 4VPy. Otherwise, dispersant II is manufactured using the same method as dispersant I. The mass ratio of each component unit of dispersant II (MMA / BMA / MPEG9MA / DM) is 35.1 / 0.1 / 17.4 / 47.4.

[0108] (Preparation of Dispersant III)

[0109] DMAPAA (registered trademark) is used instead of 4VPy. Otherwise, dispersant III is manufactured using the same method as dispersant I. The mass ratio of each component unit of dispersant III (MMA / BMA / MPEG9MA / DMAPAA) is 35.3 / 0.1 / 17.5 / 47.1.

[0110] (Preparation of Dispersant IV)

[0111] DE is used instead of 4VPy. Otherwise, dispersant IV is manufactured using the same method as dispersant I. The mass ratio of each component unit of dispersant IV (MMA / BMA / MPEG9MA / DE) is 53.1 / 0.1 / 26.2 / 20.6.

[0112] [Example 1]

[0113] In a polyethylene container, 9.6 parts by weight of perylene black (BASF, Lumogen (registered trademark) Black FK4280), 2.4 parts by weight of derivative 1 (chemical formula 1), 6.0 parts by weight of dispersant I (based on solids content), and PMA as a solvent were used. The amount of PMA was adjusted to 100 parts by weight of perylene black + derivative + dispersant + solvent. Zirconia beads were then added. 300 parts by mass were added into a container and dispersed for 60 minutes using a paint shaker manufactured by Asada Iron Works Co., Ltd. to obtain the black pigment dispersion of the example (perylene black concentration 9.6% by mass, derivative concentration 2.4% by mass, dispersant concentration 6.0% by mass).

[0114] [Example 2]

[0115] The dispersant II, which is converted to 6.0 parts by weight of solids, was used as the dispersant. Otherwise, the black pigment dispersion of Example 2 was obtained in the same manner as in Example 1.

[0116] [Example 3]

[0117] The dispersant III, which is converted to 6.0 parts by weight of solids, was used as the dispersant. Otherwise, the black pigment dispersion of Example 3 was obtained in the same manner as in Example 1.

[0118] [Comparative Example 1]

[0119] The black pigment dispersion of Comparative Example 1 was obtained in the same manner as in Example 1, except that the perylene black was 12.0 parts by weight and no derivatives were used.

[0120] [Comparative Example 2]

[0121] The perylene black was made in a quantity of 12.0 parts by weight, without the use of derivatives, and otherwise the black pigment dispersion of Comparative Example 2 was obtained in the same manner as in Example 2.

[0122] [Comparative Example 3]

[0123] The perylene black was made in a quantity of 12.0 parts by weight, without the use of derivatives, and otherwise the black pigment dispersion of Comparative Example 3 was obtained in the same manner as in Example 3.

[0124] [Comparative Example 4]

[0125] Using 2.4 parts by weight of Solsperse 5000 (registered trademark) (Lubrizol Corporation, Japan / containing sulfonic acid group (ammonium salt)) as a derivative, the black pigment dispersion of Comparative Example 4 was obtained in the same manner as in Example 1.

[0126] [Comparative Example 5]

[0127] Using 2.4 parts by mass of derivative 2 (a derivative having a secondary amino group) as the derivative, the black pigment dispersion of Comparative Example 5 was obtained in the same manner as in Example 1.

[0128] [Comparative Example 6]

[0129] Using 2.4 parts by mass of derivative 3 (a derivative having a secondary amino group) as a derivative, the black pigment dispersion of Comparative Example 6 was obtained in the same manner as in Example 1.

[0130] [Comparative Example 7]

[0131] Using 2.4 parts by mass of derivative 4 (a derivative having a carboxyl group) as a derivative, the black pigment dispersion of Comparative Example 7 was obtained in the same manner as in Example 1.

[0132] [Comparative Example 8]

[0133] Using 2.4 parts by mass of derivative 5 (a derivative having a carboxyl group) as a derivative, the black pigment dispersion of Comparative Example 8 was obtained in the same manner as in Example 1.

[0134] <Particle size determination of perylene black>

[0135] The black pigment dispersions of Examples 1-3 and Comparative Examples 1-8 were diluted with PMA to a concentration range of 0.001-10% by mass, and the average particle size (cumulative average particle size; average particle size obtained by cumulative analysis) was determined using an FPAR-1000 manufactured by Otsuka Electronics Co., Ltd. The average particle size was measured immediately after preparation and after storage in a constant temperature chamber at 40°C for 1 week.

[0136] <Viscosity Determination of Black Pigment Dispersions>

[0137] The viscosity (25°C) of the black pigment dispersions of Examples 1-3 and Comparative Examples 1-8 immediately after preparation and after storage in a constant temperature chamber at 40°C for one week was determined using an E-type viscometer (TV-22) manufactured by Toki Kogyo Co., Ltd.

[0138] Table 3 shows the results of the following for the black pigments, derivatives, and functional groups of the black pigments and derivatives in Examples 1-3 and Comparative Examples 1-8: functional groups of the derivatives, dispersants, amine values ​​(mgKOH / g) of the dispersants, solvents, average particle size (particle size A is the average particle size (nm) immediately after preparation, and particle size B is the average particle size (nm) after storage in a constant temperature chamber at 40°C for 1 week), particle size change rate (particle size B / particle size A), viscosity (viscosity A is the viscosity (mPa·s / 25°C) immediately after preparation, and viscosity B is the viscosity (mPa·s / 25°C) after storage in a constant temperature chamber at 40°C for 1 week), viscosity change rate (viscosity B / viscosity A), and practicality assessment.

[0139] In Examples 1-3 and Comparative Examples 4-8, the pigment concentration was 9.6% by mass, and in Comparative Examples 1-3, the pigment concentration was 12.0% by mass. Additionally, in Examples 1-3 and Comparative Examples 4-8, the derivative concentration was 2.4% by mass. In all examples and comparative examples in Table 3, the dispersant concentration was 6.0% by mass, and the solvent concentration was 82.0% by mass.

[0140] Practicality is determined as follows:

[0141] Project 1) The average particle size immediately after preparation is below 200 nm, and the particle size change rate is 0.85 to 1.15.

[0142] Project 2) The viscosity of the freshly prepared product is below 10 (mPa·s / 25℃), and the viscosity change rate is 0.85~1.15;

[0143] For these two items, those that meet both criteria will be marked as "○", and those that do not will be marked as "×".

[0144] [Table 3]

[0145]

[0146] Comparative Examples 2, 3, 5, and 6 gelled during preparation, making it impossible to determine the average particle size and viscosity. Comparative Examples 1 and 4 did not meet both items 1) and 2), while Comparative Examples 7 and 8 only failed to meet one of them; therefore, their practicality was judged as "×".

[0147] On the other hand, Examples 1 to 3 meet both items 1) and 2), and their practicality is judged as "○".

[0148] Comparing Examples 1-3 with Comparative Examples 1-3, it was confirmed that even when the types of pigments and dispersants are the same, using Derivative 1 as the derivative improves the dispersibility of perylene black and reduces the particle size change rate and viscosity change rate. Furthermore, comparing Example 1 with Comparative Examples 4-8, it was confirmed that even when the types and concentrations of pigments and dispersants are the same, and the derivative concentrations are also the same, using a derivative without sulfonic acid groups causes the pigment dispersion to gel, or increases the particle size change rate or viscosity change rate.

[0149] [Example 4]

[0150] Using 2.4 parts by mass of derivative 6 as a derivative, the black pigment dispersion of Example 4 was obtained in the same manner as in Example 1.

[0151] [Example 5]

[0152] Using 2.4 parts by weight of derivative 7 as the derivative, the black pigment dispersion of Example 5 was obtained in the same manner as in Example 1.

[0153] [Example 6]

[0154] Using 9.6 parts by weight of perylene black (BASF Corporation, Paliogen (registered trademark) Black S0084) as the black pigment, the black pigment dispersion of Example 6 was obtained in the same manner as in Example 1.

[0155] [Comparative Example 9]

[0156] Using 2.4 parts by mass of derivative 8 (a derivative having sulfonic acid groups (aluminum salts)) as a derivative, the black pigment dispersion of Comparative Example 9 was obtained in the same manner as in Example 1.

[0157] [Comparative Example 10]

[0158] Using 2.4 parts by weight of derivative 8 (a derivative having sulfonic acid groups (aluminum salts)) as a derivative, the black pigment dispersion of Comparative Example 10 was obtained in the same manner as in Example 2.

[0159] [Comparative Example 11]

[0160] Using 2.4 parts by weight of derivative 8 (a derivative having sulfonic acid groups (aluminum salts)) as a derivative, the black pigment dispersion of Comparative Example 11 was obtained in the same manner as in Example 3.

[0161] [Comparative Example 12]

[0162] Dispersant IV, which is converted to 6.0 parts by weight of solids, was used as the dispersant. Otherwise, the black pigment dispersion of Comparative Example 12 was obtained in the same manner as in Example 1.

[0163] Table 4 shows the results of the following for the black pigments, derivatives, and functional groups of the black pigments and derivatives in Examples 4-6 and Comparative Examples 9-12: functional groups, dispersants, amine values ​​(mgKOH / g) of the dispersants, solvents, average particle size (particle size A is the average particle size immediately after preparation (nm), and particle size B is the average particle size after storage in a constant temperature chamber at 40°C for 1 week (nm)), particle size change rate (particle size B / particle size A), viscosity (viscosity A is the viscosity immediately after preparation (mPa·s / 25°C), and viscosity B is the viscosity after storage in a constant temperature chamber at 40°C for 1 week (mPa·s / 25°C)), viscosity change rate (viscosity B / viscosity A), and practicality assessment.

[0164] [Table 4]

[0165]

[0166] Comparative Examples 10 and 11 gelled after being stored at 40°C for one week, and their average particle size and viscosity could not be measured after storage. Comparative Examples 9 and 12 had appropriate measured values ​​of average particle size and viscosity during preparation, but their particle size change rate and viscosity change rate exceeded the reference value, indicating insufficient stability. Therefore, their practicality was judged as "×".

[0167] On the other hand, Examples 4 to 6 meet both items 1) and 2), and their usability is judged as "○".

[0168] Based on Tables 3 and 4, it was confirmed that black pigment dispersions using perylene black as a black pigment, by combining any of the derivatives shown in Formula 1, Formula 2 or Formula 3 with sulfonic acid groups as functional groups with specific dispersants, not only during preparation but also after storage tests, exhibit excellent dispersibility and stability of the pigment, with average particle size and viscosity remaining within appropriate ranges.

[0169] Patent document 5 disclosed the use of derivative 8 as a derivative in pigment dispersions. However, as shown in Tables 3 and 4, for black pigment dispersions using perylene black as a black pigment, the improvement in dispersibility is insufficient when using derivative 8. For the first time, it was confirmed that by combining derivatives such as derivative 1, which have sulfonic acid groups (free acids), with specific dispersants, dispersibility and stability can be improved.

[0170] Industrial availability

[0171] The black pigment dispersion of the present invention is useful in the fields of displays, solid-state imaging elements, infrared sensors, etc.

Claims

1. A black pigment dispersion comprising at least a black pigment, a derivative, a dispersant, and a solvent. The black pigment is perylene black. The derivative is any one of the derivatives represented by chemical formula 1, chemical formula 2, or chemical formula 3. The dispersant is a copolymer composed of monomer A having the chemical formula 4, monomer B having a basic functional group, and monomer C capable of polymerizing with said A and said B. The monomer B is a monomer having a nitrogen-containing aromatic heterocyclic group as a basic functional group and / or a monomer having the structure of chemical formula 5. The amine value of the dispersant is 120 mg KOH / g to 200 mg KOH / g. Chemical Formula 1 Chemical formula 2 In chemical formula 2, n = 1 to 2. Chemical formula 3 CH2=C(R1)COO(CH2CH2O) n R2 ··· Chemical Formula 4 In chemical formula 4, R1 is hydrogen or methyl, R2 is an alkyl group with 1 to 8 carbon atoms, and n = 4 to 23. CH2=C(R3)-AB-NR4R5 ··· Chemical Formula 5 In chemical formula 5, R3 is hydrogen or methyl, A is -COO- or -CONH-, B is an alkylene group with 1 to 6 carbon atoms, and R4 and R5 are independently hydrogen or alkyl groups with 1 to 3 carbon atoms. R4 and R5 can bond together with the adjacent nitrogen atom to form a 5 to 7-membered heterocycle.

2. The black pigment dispersion according to claim 1, wherein, The perylene black is the perylene black shown in chemical formula 6 and / or chemical formula 7. Chemical Formula 6 Chemical formula 7.

3. The black pigment dispersion according to claim 1 or 2, wherein, The average particle size of the perylene black is below 200 nm.

4. The black pigment dispersion according to claim 1 or 2, wherein, The content of the black pigment is 5% to 25% by mass of the total mass of the black pigment dispersion. The content of the derivative is 5% to 50% by mass relative to the pigment. The content of the dispersant is 5% to 80% by mass relative to the total mass of the pigment and derivative.

5. The black pigment dispersion according to claim 3, wherein, The content of the black pigment is 5% to 25% by mass of the total mass of the black pigment dispersion. The content of the derivative is 5% to 50% by mass relative to the pigment. The content of the dispersant is 5% to 80% by mass relative to the total mass of the pigment and derivative.

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