Black pigment dispersion

Abstract

To prevent a dispersion from becoming gel or the dispersion from undergoing a change of viscosity during storage when preparing a pigment dispersion containing perylene black, leading to improved dispersibility of perylene black.SOLUTION: A black pigment dispersion comprises a combination of: perylene black; any derivative represented by chemical formulas 1-3; and a dispersant that is a copolymer comprising a monomer A having a structure of chemical formula 4, a monomer B having a basic functional group, and a monomer C polymerizable with the monomer A and the monomer B, the monomer B being a monomer having a nitrogen-containing heteroaromatic ring group as a basic functional group and / or a monomer having a structure of chemical formula 5, with an amine value of 120 mgKOH / g or more and 200 mgKOH / g or less. The content of perylene black is 5 mass% or more and 25 mass% or less. The perylene black preferably has its average particle size to be controlled to 200 nm or less.SELECTED DRAWING: None

Description

[Technical field]

[0001] The present invention relates to a black pigment dispersion containing perylene black and having excellent dispersibility. [Background technology]

[0002] A liquid crystal display device has a liquid crystal cell structure in which a liquid crystal material is filled between two glass substrates each having a transparent electrode facing each other. A column spacer is inserted between the two glass substrates to maintain a uniform gap between the substrates and provide a good image. Conventionally, bead spacers such as bead-like glass have been used as such column spacers. However, it has been pointed out that the method using bead spacers has problems such as light leakage problems due to the beads being randomly dispersed in the gap, the gap distance being likely to vary widely, and it is difficult to control mechanical properties such as elasticity. In addition, more precise gap control is required due to the market demand for higher image quality for liquid crystal display devices in recent years.

[0003] As an improvement measure, black column spacers using a black photosensitive resin composition instead of bead spacers have been proposed (Patent Documents 1 and 2). With black column spacers, it is possible to form column spacers at desired positions so that the variation in gap distance is small, and it is relatively easy to control the properties of photopolymerizable components, etc., so it is considered that more precise gap control is possible than with bead spacers. Furthermore, by including a black colorant in the column spacer, it is expected that visible light (wavelength 380 nm to 750 nm) is blocked, and the contrast and coloring effect are improved. Patent Documents 1 and 2 exemplify perylene black as such a black colorant. Furthermore, Patent Document 3 discloses a pigment of a specific structure as an example of perylene black.

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

[0005] Patent Document 5 discloses a color filter coloring composition that has excellent dispersibility, good fluidity, stability, and developability, and that contains a colorant, a resin-type dispersant, and a solvent, in which the colorant contains a pigment having an average primary particle size of 20 nm to 50 nm and an aspect ratio of the pigment particles of 1:1 to 1:3.5, and the resin-type dispersant contains an A-B block copolymer or a BAB block copolymer consisting of an A block having solvent affinity and a B block having a functional group containing a nitrogen atom, and an acrylic block copolymer having an amine value of 10 mgKOH / g or more and 99 mgKOH / g or less in terms of effective solid content. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] JP 2015-191234 A [Patent Document 2] JP 2007-71994 A [Patent Document 3] Patent No. 4980727 [Patent Document 4] JP 2017-226821 A [Patent Document 5] JP 2012-212054 A Summary of the Invention [Problem to be solved by the invention]

[0007] Since perylene black has excellent light-shielding properties, a black matrix formed using a black coloring composition containing perylene black has excellent display contrast in a color liquid crystal display device, and furthermore, since it has low dielectric constant properties, it is less likely to cause problems due to the electrical properties of the black matrix, such as disturbance of liquid crystal alignment and conduction between electrodes formed on a thin film transistor (TFT) substrate. In addition, since it has excellent transmittance in the near infrared region, mask alignment work is also possible, and it is also suitable as a driving substrate for a TFT type color liquid crystal display device.

[0008] Perylene black has a drawback in that it has poor dispersibility, and as disclosed in Patent Document 5, a dispersant has been used to improve the dispersibility in a black coloring composition (black pigment dispersion). However, even if the dispersibility during preparation of the black pigment dispersion can be improved, the dispersibility may decrease during storage, leading to an increase in particle size or gelation. In addition, the viscosity of the dispersion may increase, and there was a need to further improve the dispersibility of perylene black.

[0009] An object of the present invention is to provide a black pigment dispersion containing perylene black as a black pigment, which has excellent dispersibility not only during preparation but also during storage. [Means for solving the problem]

[0010] As a result of intensive research conducted by the present inventors to solve the above problems, they discovered that when perylene black is used as a black pigment in a pigment dispersion, the dispersibility of perylene black can be improved by using it in combination with a specific derivative and a dispersant, and thus completed the present invention.

[0011] Specifically, the present invention provides A black pigment dispersion containing at least a black pigment, a derivative, a dispersant and a solvent, The black pigment is perylene black, The derivative is a derivative represented by any one of Chemical Formula 1, Chemical Formula 2, and Chemical Formula 3, The dispersant is Monomer A having the structure of formula 4; A monomer B having a basic functional group; A monomer C polymerizable with said A and said B; A copolymer consisting of The monomer B is a monomer having a nitrogen-containing aromatic heterocyclic group as a basic functional group and / or a monomer having a structure of Chemical Formula 5, The amine value of the dispersant is 120 mgKOH / g or more and 200 mgKOH / g or less. This relates to a black pigment dispersion.

[0012] [ka]

[0013] [ka]

[0014] (In chemical formula 2, n=1 to 2.)

[0015] [ka]

[0016] [ka]

[0017] (In Chemical Formula 4, R1 is hydrogen or a methyl group; R2 is an alkyl group having 1 to 8 carbon atoms; and n=4 to 23.)

[0018] [ka]

[0019] (In Chemical Formula 5, R3 is hydrogen or a methyl group; A is -COO- or -CONH-; B is an alkylene group having 1 to 6 carbon atoms; R4 and R5 are each independently hydrogen or an alkyl group having 1 to 3 carbon atoms, and R4 and R5 may be bonded to form a 5- to 7-membered heterocycle together with the adjacent nitrogen atom.)

[0020] The black pigment dispersion of the present invention uses a derivative represented by any one of Chemical Formulas 1 to 3 in combination with a specific polymer dispersant, and is therefore superior in dispersibility and stability of perylene black to conventional perylene black-containing black pigment dispersions.

[0021] The perylene black is preferably the perylene black represented by Chemical Formula 6 and / or Chemical Formula 7.

[0022] [ka]

[0023] [ka]

[0024] The average particle size (cumulant average particle size) of the perylene black is preferably 200 nm or less, more preferably 170 nm or less. If the average particle size is 200 nm or less, the dispersibility of the perylene black is excellent. However, even if the average particle size is 170 nm or less, it is necessary that the particles do not aggregate over time (dispersion stability), and from the viewpoints of dispersion stability, light blocking properties, etc., the average particle size is preferably 50 nm or more.

[0025] The content of the black pigment is preferably 5% by mass to 25% by mass, more preferably 8% by mass to 15% by mass, of the total mass of the black pigment dispersion. If it is less than 5% by mass, the pigment concentration is low and coloring may be insufficient, while if it exceeds 25% by mass, the viscosity becomes high, which may cause problems such as poor handleability.

[0026] From the viewpoint of dispersion stability, the content of the derivative is preferably from 5% by mass to 50% by mass, and more preferably from 10% by mass to 40% by mass, relative to the pigment mass (the mass of the pigment contained in the black pigment dispersion).

[0027] From the viewpoint of optical properties such as dispersion stability, OD value, and color purity, the content of the dispersant is preferably 5% by mass or more and 80% by mass or less, and more preferably 20% by mass or more and 60% by mass or less, based on the total mass of the pigment and the derivative (the total mass of the pigment and the derivative contained in the black pigment dispersion). However, the optimal content of the derivative and the dispersant can be appropriately adjusted depending on the types and combinations of the pigment, the derivative, and the dispersant used.

[0028] The black pigment dispersion of the present invention may further contain an acrylic resin having an acidic group, a polyester resin, or a resin having a cardo structure. By containing such a resin, the effect of improving the developability and adhesion can be obtained.

[0029] The black pigment dispersion of the present invention may further contain auxiliary ingredients such as a viscosity modifier. Effect of the Invention

[0030] The black pigment dispersion of the present invention has excellent dispersibility of perylene black, does not gel during preparation, and is resistant to changes in average particle size and viscosity during storage. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0031] Hereinafter, an embodiment of the present invention will be described.

[0032] (Black pigment) As the perylene black, a known black organic pigment having a perylene structure can be used, for example, CI Pigment Black 31, CI Pigment Black 32, and perylene black represented by Chemical Formula 6 and / or Chemical Formula 7 can be used. Only one type of perylene black may be used, or two or more types may be used. In addition, a commercially available perylene black can be used, for example, Lumogen (registered trademark) Black FK4280 (BASF), Paliogen (registered trademark) Black S0084 (BASF / CI Pigment Black 31), etc. can be used. Lumogen (registered trademark) Black FK4280 has a structure represented by Chemical Formula 6 or Chemical Formula 7.

[0033] (derivative) The derivative used in the present invention is any of the derivatives shown in Chemical Formula 1, Chemical Formula 2, and Chemical Formula 3. Only one of these derivatives may be used, or two or more of these derivatives may be used. These derivatives can be synthesized and used according to a standard method. All of the derivatives shown in Chemical Formulas 1 to 3 have a sulfonic acid group, but a free acid is used instead of a metal salt.

[0034] (Dispersant) As the monomer A, a monomer corresponding to the Light Acrylate series manufactured by Kyoeisha Chemical Co., Ltd. or the New Frontier (registered trademark) series manufactured by Daiichi Kogyo Seiyaku Co., Ltd. can be used.

[0035] Monomer B is a monomer having a nitrogen-containing aromatic heterocyclic group as a basic functional group and / or a monomer having a structure of Chemical 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 a structure of Chemical Formula 5, a monomer corresponding to the Light Ester series manufactured by Kyoeisha Chemical Co., Ltd., the Cosylmer (registered trademark) series manufactured by KJ Chemicals Co., Ltd., etc. can be used.

[0036] From the viewpoint of not affecting the dispersibility of the pigment, a nonionic monomer is preferable as the monomer C. As the nonionic monomer, a (meth)acrylic acid alkyl ester such as methyl methacrylate or butyl methacrylate is preferable.

[0037] The contents of monomers A to C in the dispersant can be appropriately changed so that the total is 100 parts by mass, with monomer A being 10 to 60 parts by mass, monomer B being 10 to 50 parts by mass, and monomer C being 20 to 60 parts by mass.

[0038] The acid value and amine value of the dispersant, which is a copolymer of monomers A to C, are determined by the functional groups contained in the copolymer and their contents. The acid value (acid value calculated as solid content) can be determined, for example, by a method conforming to DIN EN ISO 2114, and the amine value (amine value calculated as solid content) can be determined, for example, by a method conforming to DIN 16945. The acid value of the dispersant is preferably 1 mgKOH / g or less. The amine value of the dispersant is preferably 120 mgKOH / g or more and 200 mgKOH / g or less, and more preferably 150 mgKOH / g or more and 180 mgKOH / g or less.

[0039] (solvent) As the solvent, various organic solvents such as aromatic, ketone, ester, glycol ether, alcohol, aliphatic, etc. may be used. The organic solvent may be used alone or in combination of two or more kinds.

[0040] Examples of aromatic organic solvents include aromatic hydrocarbons such as toluene, xylene, and ethylbenzene.

[0041] Examples of the ketone-based organic solvent include methyl ethyl ketone, methyl isobutyl ketone, diisobutyl ketone, acetylacetone, isophorone, acetophenone, and cyclohexanone.

[0042] Examples of ester-based organic solvents include ethyl acetate, n-butyl acetate, isobutyl acetate, isopropyl acetate, methyl propionate, 3-methoxybutyl acetate, ethyl 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-butylene glycol diacetate.

[0043] Examples of glycol ether-based organic solvents include water-soluble glycol ethers such as ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol mono-n-propyl ether, ethylene glycol mono-iso-propyl ether, diethylene glycol mono-iso-propyl ether, ethylene glycol mono-n-butyl ether, diethylene glycol mono-n-butyl ether, triethylene glycol mono-n-butyl ether, ethylene glycol mono-t-butyl ether, diethylene glycol mono-t-butyl ether, 1-methyl-1-methoxybutanol, propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol mono-t-butyl ether, propylene glycol mono-n-propyl ether, propylene glycol mono-iso-propyl ether, dipropylene glycol monomethyl ether, dipropylene glycol monoethyl ether, dipropylene glycol mono-n-propyl ether, dipropylene glycol mono-iso-propyl ether, propylene glycol mono-n-butyl ether, and dipropylene glycol mono-n-butyl ether; Examples of water-insoluble glycol ethers include 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.

[0044] Examples of the alcohol-based organic solvent include alkyl alcohols having 1 to 4 carbon atoms, such as ethanol, methanol, butanol, propanol, and isopropanol; Examples of the glycol include ethylene glycol, propylene glycol, diethylene glycol, pentamethylene glycol, trimethylene glycol, 2-butene-1,4-diol, 2-ethyl-1,3-hexanediol, 2-methyl-2,4-pentanediol, tripropylene glycol, polyethylene glycols with a molecular weight of 2000 or less, 1,3-propylene glycol, isopropylene glycol, isobutylene glycol, 1,4-butanediol, 1,3-butanediol, 1,5-pentanediol, 1,6-hexanediol, glycerin, mesoerythritol, and pentaerythritol.

[0045] Examples of the aliphatic organic solvent include aliphatic hydrocarbons such as n-pentane, n-hexane, and n-heptane.

[0046] From the viewpoint of ease of handling, the content of the solvent is preferably adjusted so that the solid content concentration including the pigment etc. is 6 to 40% by weight.

[0047] <Production Example of Black Pigment Composition> A black pigment dispersion was produced using the following raw materials and production method.

[0048] (Black pigment) As perylene black, Lumogen (registered trademark) Black FK4280 (BASF) and Paliogen (registered trademark) Black S0084 (BASF) were used.

[0049] (derivative) As the derivatives, derivatives 1 to 8 and Solsperse (registered trademark) 5000 (Lubrizol Japan Co., Ltd. / having a sulfonic acid group (ammonium salt)) were used.

[0050] (Production method of derivative 1) 20 parts by mass of CI Pigment Yellow 138 (BASF, Paliotol (registered trademark) Gelb K0961HD) and 300 parts by mass of 98% concentrated sulfuric acid were placed in a 500 mL separable flask and reacted at 120 ° C for 5 hours to obtain a sulfonated phthalimide quinophthalone compound. The reaction mixture was poured into 3000 parts by mass of water while stirring to precipitate a sulfonated phthalimide quinophthalone compound, and after stirring for 30 minutes, filtration and washing with water were repeated three times. The obtained wet cake was washed with 300 parts by mass of 1% diluted sulfuric acid, filtered, and washed with water. It was dried in a hot air dryer to obtain 54 parts by mass of derivative 1 represented by chemical formula 1.

[0051] The resulting derivative 1 was subjected to mass spectrometry using a Hewlett-Packard liquid chromatography mass spectrometer "LC / MS" (Electro Spray Ionization), and as a result, m / z=773 [MH]- was detected.

[0052] (Production method of derivative 2) According to a conventional method, derivative 2 represented by chemical formula 8 was obtained.

[0053] [ka]

[0054] (Production method of derivative 3) According to a conventional method, derivative 3 represented by chemical formula 9 was obtained.

[0055] [ka]

[0056] (Production method of derivative 4) According to a conventional method, derivative 4 represented by chemical formula 10 was obtained.

[0057] [ka]

[0058] (Production method of derivative 5) According to a conventional method, derivative 5 represented by chemical formula 11 was obtained.

[0059] [ka]

[0060] (Production method of derivative 6) 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 allowed to react for 5 hours at 85° C. Next, this solution was added to 1 L of ice water, and filtered and washed with water to obtain 19.5 parts by mass of (4-aminophthalimidomethyl)-CI Pigment Orange 43 into which one 4-aminophthalimidomethyl group had been introduced.

[0061] Next, 10 parts by mass of (4-aminophthalimidomethyl)-CI Pigment Orange 43 was dispersed in 100 parts by mass of water, and 3.6 parts by mass of cyanuric chloride, an amount that reacts with one amino group, was added and reacted for 1 hour at 30° C. Next, 3.4 parts by mass of orthanilic acid (2-aminobenzenesulfonic acid) was added and reacted for 2 hours at 80° C. to hydrolyze the remaining Cl, thereby obtaining 15.2 parts by mass of Derivative 6 represented by Chemical Formula 2.

[0062] 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 measured in positive ion mode using α-cyano-4-hydroxycinnamic acid (CHCA) as the matrix. As a result, a peak was observed at m / z=854. This ion peak corresponds to the compound with n=1.

[0063] (Production method of derivative 7) 18.4 parts by mass of cyanuric chloride and 17.3 parts by mass of orthanilic acid in an amount that reacts with one chlorine atom of cyanuric chloride were added to 100 parts by mass of water, and the mixture was allowed to react at 10° C. for 1 hour. 16.6 parts by mass of 3-amino-4-methoxybenzamide in an amount that reacts with two chlorine atoms of the reaction product were added to the reaction product, and the mixture was allowed to react at 85° C. for 1 hour. The reaction product was filtered, and the resulting residue was washed with water, and then allowed to stand overnight in a thermostatic chamber at 100° C. and dried, to obtain 32.5 parts by mass of derivative 3 represented by chemical formula 3.

[0064] Using an AXIMA CFR plus matrix-assisted laser desorption / ionization-time of flight mass spectrometer (Shimadzu Corporation), the molecular ion peak of derivative 7 was measured in positive ion mode using α-cyano-4-hydroxycinnamic acid (CHCA) as the matrix. As a result, a peak was observed at m / z = 582.

[0065] (Production method of derivative 8) According to the method described in paragraph

[0148] of JP2012-212054A, derivative 8, which is an aluminum salt of derivative 1, was obtained.

[0066] (solvent) Propylene glycol monomethyl ether acetate (PMA) was used as the solvent.

[0067] (Dispersant) Dispersants I to IV, which will be described later, were used as the dispersants. The amine value, Mp (peak top molecular weight), Mw / Mn (ratio of weight average molecular weight to number average molecular weight), NV (solid content or non-volatile content), and monomer composition (numbers indicate mass ratios of monomers) constituting each dispersant are as shown in Table 1. In Table 1, the structures indicated by the abbreviations in the monomer composition column are as shown in Table 2.

[0068] [Table 1]

[0069] [Table 2]

[0070] (Method of producing dispersant I) 287.3 parts by mass of methyl methacrylate (MMA), 0.6 parts by mass of butyl methacrylate (BMA), 142.4 parts by mass of methoxypolyethylene glycol methacrylate (MPEG9MA), 15 parts by mass of N-(tert-butyl)-N-(1-diethylphosphono-2,2-dimethylpropyl)-O-(2-carboxylprop-2-yl)hydroxylamine (Arkema, product name BlocBuilder MA), 436 parts by mass of propylene glycol monomethyl ether acetate (PMA), and 218 parts by mass of propylene glycol monomethyl ether (PM) were collected in a 2L stainless steel separable flask. The mixture was stirred with nitrogen bubbling, and the flask was heated to 125°C in an oil bath to react for 4 hours.

[0071] Next, 199.7 parts by mass of 4-vinylpyridine (4VPy), 196 parts by mass of PMA, and 98 parts by mass of PM were charged into the flask, and the mixture was stirred while continuously bubbling with nitrogen, and reacted at 125° C. for 4 hours.

[0072] The solid content of the reaction mixture was 40.5% by weight. The block copolymer obtained was measured by GPC (gel permeation chromatography) to find that the peak top molecular weight was 11,500 and the Mw / Mn was 1.24. The amine value (solid content) was 168.6 mgKOH / g.

[0073] The block copolymer (dispersant I) thus obtained has a block having a constituent unit derived from MMA (monomer C), a constituent unit derived from BMA (monomer C), and a constituent unit derived from MPEG9MA (monomer A), and a block having a constituent unit derived from 4VPy (monomer B) as a basic group-containing unit. That is, dispersant I is a linear block polymer having a block consisting of a basic group-containing unit at one end. Due to the monomer structure, dispersant I does not have an acidic group. The mass ratio of each constituent unit of dispersant I (MMA / BMA / MPEG9MA / 4VPy) is 45.6 / 0.1 / 22.6 / 31.7.

[0074] (Production of Dispersant II) Dispersant II was produced in the same manner as Dispersant I, except that DM was used instead of 4VPy. The mass ratio of each constituent unit of Dispersant II (MMA / BMA / MPEG9MA / DM) was 35.1 / 0.1 / 17.4 / 47.4.

[0075] (Production of Dispersant III) Dispersant III was produced in the same manner as Dispersant I, except that DMAPAA (registered trademark) was used instead of 4VPy. The mass ratio of each constituent unit of Dispersant III (MMA / BMA / MPEG9MA / DMAPAA) was 35.3 / 0.1 / 17.5 / 47.1.

[0076] (Manufacture of Dispersant IV) Dispersant IV was prepared in the same manner as Dispersant I, except that DE was used instead of 4VPy. The mass ratio of each constituent unit of Dispersant IV (MMA / BMA / MPEG9MA / DE) was 53.1 / 0.1 / 26.2 / 20.6.

[0077] [Example 1] In a polyethylene container, 9.6 parts by mass of perylene black (BASF, Lumogen (registered trademark) Black FK4280), 12.4 parts by mass of the derivative represented by Chemical Formula 1 as a derivative, 6.0 parts by mass of Dispersant I as a dispersant in terms of solid content, and PMA as a solvent were collected. The amount of PMA was adjusted so that "perylene black + derivative + dispersant + solvent" was 100 parts by mass. 300 parts by mass of zirconia beads (φ0.5 mm) were placed in the container and dispersed for 60 minutes using a paint shaker manufactured by Asada Iron Works Co., Ltd., to obtain a 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).

[0078] [Example 2] A black pigment dispersion of Example 2 was obtained in the same manner as in Example 1, except that Dispersant II was used as the dispersant in an amount of 6.0 parts by mass in terms of solid content.

[0079] [Example 3] A black pigment dispersion of Example 3 was obtained in the same manner as in Example 1, except that Dispersant III was used in an amount of 6.0 parts by mass in terms of solid content as the dispersant.

[0080] [Comparative Example 1] A black pigment dispersion of Comparative Example 1 was obtained in the same manner as in Example 1, except that the amount of perylene black was 12.0 parts by mass and no derivative was used.

[0081] [Comparative Example 2] A black pigment dispersion of Comparative Example 2 was obtained in the same manner as in Example 2, except that the amount of perylene black was 12.0 parts by mass and no derivative was used.

[0082] [Comparative Example 3] A black pigment dispersion of Comparative Example 3 was obtained in the same manner as in Example 3, except that the amount of perylene black was 12.0 parts by mass and no derivative was used.

[0083] [Comparative Example 4] A black pigment dispersion of Comparative Example 4 was obtained in the same manner as in Example 1, except that 2.4 parts by mass of Solsperse (registered trademark) 5000 (Lubrizol Japan Co., Ltd. / having a sulfonic acid group (ammonium salt)) was used as the derivative.

[0084] [Comparative Example 5] A black pigment dispersion of Comparative Example 5 was obtained in the same manner as in Example 1, except that 2.4 parts by mass of Derivative 2 (a derivative having a secondary amino group) was used as the derivative.

[0085] [Comparative Example 6] A black pigment dispersion of Comparative Example 6 was obtained in the same manner as in Example 1, except that 2.4 parts by mass of Derivative 3 (a derivative having a secondary amino group) was used as the derivative.

[0086] [Comparative Example 7] A black pigment dispersion of Comparative Example 7 was obtained in the same manner as in Example 1, except that 2.4 parts by mass of Derivative 4 (a derivative having a carboxyl group) was used as the derivative.

[0087] [Comparative Example 8] A black pigment dispersion of Comparative Example 8 was obtained in the same manner as in Example 1, except that 2.4 parts by mass of Derivative 5 (a derivative having a carboxyl group) was used as the derivative.

[0088] <Particle size measurement of perylene black> The black pigment dispersions of Examples 1 to 3 and Comparative Examples 1 to 8 were diluted with PMA to a concentration range of 0.001 to 10% by mass, and then the average particle size (cumulant average particle size; average particle size by cumulant analysis) was measured using an FPAR-1000 manufactured by Otsuka Electronics Co., Ltd. The average particle size was measured immediately after preparation and after storage for one week in a thermostatic chamber at 40°C.

[0089] <Viscosity measurement of black pigment dispersion> The viscosities (25°C) of the black pigment dispersions of Examples 1 to 3 and Comparative Examples 1 to 8 immediately after preparation and after storage for one week in a thermostatic chamber at 40°C were measured using an E-type viscometer (TV-22) manufactured by Toki Sangyo Co., Ltd.

[0090] Table 3 shows the black pigment, derivative, functional groups possessed by the derivative, dispersant, amine value (mgKOH / g) of the dispersant, solvent, 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 for one week in a constant temperature chamber at 40°C), rate of change in particle size (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 for one week in a constant temperature chamber at 40°C (mPa s / 25°C)), rate of change in viscosity (viscosity B / viscosity A), and the results of the practicality evaluation for the black pigment dispersions of Examples 1 to 3 and Comparative Examples 1 to 8.

[0091] The pigment concentration is 9.6% by mass in Examples 1 to 3 and Comparative Examples 4 to 8, and 12.0% by mass in Comparative Examples 1 to 3. The derivative concentration is 2.4% by mass in Examples 1 to 3 and Comparative Examples 4 to 8. All of the Examples and Comparative Examples in Table 3 have a dispersant concentration of 6.0% by mass and a solvent concentration of 82.0% by mass.

[0092] The practicality assessment is Item 1) The average particle size immediately after preparation is 200 nm or less, and the rate of change in particle size is 0.85 to 1.15; Item 2) The viscosity immediately after preparation is 10 (mPa s / 25°C) or less, and the rate of viscosity change is 0.85 to 1.15; For the two items above, if both were met, it was judged as "○", otherwise it was judged as "×".

[0093] [Table 3]

[0094] In Comparative Examples 2, 3, 5, and 6, gelation occurred during preparation, and the average particle size and viscosity could not be measured. In Comparative Examples 1 and 4, both items 1) and 2) were unsuitable, and in Comparative Examples 7 and 8, only one of them was unsuitable, and the practicality of each was judged to be "x".

[0095] On the other hand, Examples 1 to 3 met both items 1) and 2) and were judged to be "good" in terms of practicality.

[0096] Comparing Examples 1 to 3 with Comparative Examples 1 to 3, it was confirmed that even if the types and concentrations of the pigment and dispersant were the same, the dispersibility of perylene black was improved and the particle size change rate and the viscosity change rate were reduced by using Derivative 1 as the derivative. Also, comparing Example 1 with Comparative Examples 4 to 8, it was confirmed that even if the types and concentrations of the pigment and dispersant were the same and the derivative concentration was also the same, when a derivative not having a sulfonic acid group was used, the pigment dispersion gelled or the particle size change rate or viscosity change rate increased.

[0097] [Example 4] A black pigment dispersion of Example 4 was obtained in the same manner as in Example 1, except that 2.4 parts by mass of Derivative 6 was used as the derivative.

[0098] [Example 5] A black pigment dispersion of Example 5 was obtained in the same manner as in Example 1, except that 2.4 parts by mass of Derivative 7 was used as the derivative.

[0099] [Example 6] A black pigment dispersion of Example 6 was obtained in the same manner as in Example 1, except that 9.6 parts by mass of perylene black (BASF, Paliogen (registered trademark) Black S0084) was used as the black pigment.

[0100] [Comparative Example 9] A black pigment dispersion of Comparative Example 9 was obtained in the same manner as in Example 1, except that 2.4 parts by mass of Derivative 8 (a derivative having a sulfonic acid group (aluminum salt)) was used as the derivative.

[0101] [Comparative Example 10] A black pigment dispersion of Comparative Example 10 was obtained in the same manner as in Example 2, except that 2.4 parts by mass of Derivative 8 (a derivative having a sulfonic acid group (aluminum salt)) was used as the derivative.

[0102] [Comparative Example 11] A black pigment dispersion of Comparative Example 11 was obtained in the same manner as in Example 3, except that 2.4 parts by mass of Derivative 8 (derivative having a sulfonic acid group (aluminum salt)) was used as the derivative.

[0103] [Comparative Example 12] A black pigment dispersion of Comparative Example 12 was obtained in the same manner as in Example 1, except that Dispersant IV was used in an amount of 6.0 parts by mass in terms of solid content as the dispersant.

[0104] Table 4 shows the black pigment, derivative, functional groups possessed by the derivative, dispersant, amine value (mgKOH / g) of the dispersant, solvent, 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 for one week in a constant temperature chamber at 40°C), rate of change in particle size (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 for one week in a constant temperature chamber at 40°C (mPa s / 25°C)), rate of change in viscosity (viscosity B / viscosity A), and the results of the practicality evaluation for the black pigment dispersions of Examples 4 to 6 and Comparative Examples 9 to 12.

[0105] [Table 4]

[0106] In Comparative Examples 10 and 11, gelation occurred after storage at 40° C. for 1 week, and the average particle size and viscosity were not measurable after storage. In Comparative Examples 9 and 12, the average particle size and viscosity measurements were favorable at the time of preparation, but the particle size change rate and viscosity change rate exceeded the standard values, and the stability was lacking, so the practicality was judged to be “×”.

[0107] On the other hand, Examples 4 to 6 met both items 1) and 2) and were judged to be "good" in terms of practicality.

[0108] As shown in Tables 3 and 4, it was confirmed that the black pigment dispersion using perylene black as the black pigment has an average particle size and viscosity within the preferred ranges not only during preparation but also after the storage test, by combining any of the derivatives represented by Chemical Formula 1, Chemical Formula 2, or Chemical Formula 3 having a sulfonic acid group as a functional group with a specific dispersant, and thus has excellent pigment dispersibility and stability.

[0109] The above-mentioned Patent Document 5 discloses the use of Derivative 8 as a derivative in a pigment dispersion. However, as shown in Tables 3 and 4, in a black pigment dispersion using perylene black as the black pigment, Derivative 8 does not sufficiently improve dispersibility, and it has been confirmed that dispersibility and stability can be improved only by combining a derivative having a sulfonic acid group (free acid) such as Derivative 1 with a specific dispersant. [Industrial Applicability]

[0110] The black pigment dispersion of the present invention is useful in technical fields such as displays, solid-state imaging devices, and infrared sensors.

Claims

1. A black pigment dispersion containing at least a black pigment, a derivative, a dispersant and a solvent, The black pigment is perylene black, The derivative is a derivative represented by any one of Chemical Formula 1, Chemical Formula 2, and Chemical Formula 3, The dispersant is Monomer A having the structure of Chemical Formula 4; A monomer B having a basic functional group; A monomer C capable of polymerizing with said A and said B; A copolymer consisting of The monomer B is a monomer having a nitrogen-containing aromatic heterocyclic group as a basic functional group and / or a monomer having a structure represented by Chemical Formula 5, The amine value of the dispersant is 120 mgKOH / g or more and 200 mgKOH / g or less. Black pigment dispersion. 【Chemistry 1】 【Chemistry 2】 (In chemical formula 2, n=1 to 2.) 【Chemistry 3】 【Chemistry 4】 (In Chemical Formula 4, R1 is hydrogen or a methyl group; R2 is an alkyl group having 1 to 8 carbon atoms; and n=4 to 23.) 【Chemistry 5】 (In Chemical Formula 5, R3 is hydrogen or a methyl group; A is -COO- or -CONH-; B is an alkylene group having 1 to 6 carbon atoms; R4 and R5 are each independently hydrogen or an alkyl group having 1 to 3 carbon atoms, and R4 and R5 may combine 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 represented by Chemical Formula 6 and / or Chemical Formula 7. 【Chemistry 6】 【Chemistry 7】

3. 3. The black pigment dispersion according to claim 1, wherein the perylene black has an average particle size of 200 nm or less.

4. The content of the black pigment is 5% by mass or more and 25% by mass or less of the total mass of the black pigment dispersion, The content of the derivative is 5% by mass or more and 50% by mass or less based on the pigment mass, The content of the dispersant is 5% by mass or more and 80% by mass or less based on the total mass of the pigment and the derivative. The black pigment dispersion according to claim 1 .

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