Perylene-based black pigment microparticles, method for producing the same, black pigment composition containing the same, and method for producing perylene-based black pigment microparticles with controlled hue and / or chroma

Abstract

The present invention provides amorphous perylene-based black pigment microparticles having an average circularity of 0.8 or more and a method for producing the perylene-based black pigment microparticles; wherein the method for producing the perylene-based black pigment microparticles comprises a step of mixing a pigment solution in which a perylene-based black pigment is dissolved and a precipitation solvent for precipitating the perylene-based black pigment microparticles from the pigment solution to generate the perylene-based black pigment microparticles, wherein at least one of the pigment solution and the precipitation solvent independently contains an alkaline earth metal salt and / or a particle growth inhibitor. According to the present invention, perylene-based black pigment microparticles having good dispersibility, high hiding power and light-shielding power, and controlled hue and chromaticity, and a method for simply producing the microparticles can be provided.

Description

Technical Field

[0001] The present invention relates to perylene-based black pigment microparticles, a method for producing the same, a black pigment composition containing the same, and a method for producing perylene-based black pigment microparticles with controlled hue and / or chromaticity. Background Art

[0002] As black pigments, carbon black, perylene-based black pigments, etc. are traditionally used. Carbon black is the most widely used black pigment, which has the characteristics of strong tinting power, excellent blackness, acid resistance, and weather resistance. However, due to the low resistance of carbon black, it is difficult to apply it to applications requiring high resistance, such as black matrices and black columnar spacers for liquid crystal color filters (Patent Document 1). Further, when a black matrix and a black columnar spacer are formed on a glass substrate using photolithography, due to the low transmittance of carbon black in the near-infrared region, there is a problem of difficulty in alignment (Patent Document 2).

[0003] Since carbon black has such problems, Patent Documents 2 to 4 propose a method of using carbon black and a perylene-based black pigment in combination.

[0004] On the other hand, perylene pigments are widely used as strong pigments, showing red-purple-brown-black in a solid state, but their hue is not always thermally stable (Patent Document 1). Therefore, in Patent Document 1, a perylene black pigment obtained by firing at least one compound selected from perylene tetracarboxylic acid diimide derivatives and perylene diaminodicarboxylic acid diimide derivatives at a temperature of 200 to 600° C. in a vacuum or inert gas atmosphere is proposed. However, in Example 1, a perylene black pigment having a butyl group fired at 500° C. for 1 hour was prepared, but the perylene black pigment of Example 1 was compared with the unfired perylene black pigment of Comparative Example 1. Although the weather resistance and heat resistance were excellent, the blackness and tinting strength were not improved in terms of hue.

[0005] Prior art

[0006] Patent Literature

[0007] Patent Document 1: Japanese Patent Publication No. 2003-041144

[0008] Patent Document 1: Japanese Patent Publication No. 2012-068613

[0009] Patent Document 1: Japanese Patent Publication No. 10-219167

[0010] Patent Document 1: Japanese Patent Publication No. 2012-212051 Summary of the invention

[0011] Technical problem to be solved by the invention

[0012] As described above, the hue of perylene pigments is not always thermally stable. In Patent Document 1, an attempt was made to prepare a perylene black pigment having high blackness and tinting strength and excellent heat resistance and weather resistance by firing, but the blackness and tinting strength were not improved in terms of hue. In addition, CI Pigment Black 31 and CI Pigment Black 32, which are representative perylene black pigments, have a green hue due to the presence of a light absorption valley near 520 nm, which is far from so-called black.

[0013] Furthermore, compounds classified as perylene imide have the property of easily causing crystal growth and easily becoming needle-shaped crystals when colored. Therefore, when forming a paste-like pigment composition, there are problems such as poor dispersibility and difficulty in molding. In addition, the filling of pigment particles becomes sparse, and the hiding power decreases due to the generation of gaps, the blackness becomes insufficient, and when used in a display device, the display quality is poor.

[0014] In particular, in the display devices of consumer devices such as smartphones, which face fierce market competition, accurate control of the hue of black is required as one of the requirements for display quality in order to achieve product differentiation. Therefore, when using perylene-based black pigments that do not have resistance problems instead of carbon black as black pigments for display devices, there is a problem of difficulty in accurately controlling the hue as described above.

[0015] Therefore, an object of the present invention is to provide a perylene-based black pigment having high hiding power and light-shielding property and controlled hue and chroma. Another object of the present invention is to provide a method for easily producing a perylene-based black pigment.

[0016] Technical means to solve technical problems

[0017] The inventors of the present invention have made intensive studies and have found that the hue and / or chromaticity can be controlled by heat-treating amorphous perylene-based black pigment fine particles having an average circularity of 0.8 or more under varying conditions, and that a perylene-based black pigment having high hiding power and light-shielding properties and controlled hue and chromaticity can be produced, thereby completing the present invention. That is, the present invention is as follows.

[0018] [1] A first embodiment of the present invention is a perylene-based black pigment microparticle characterized in that the microparticle has an average circularity of 0.8 or more and is amorphous.

[0019] [2] A second embodiment of the present invention is the perylene-based black pigment fine particles as described in the embodiment of [1] above, characterized in that the average primary particle size is 80 nm or less.

[0020] [3] A third embodiment of the present invention is a method for producing perylene-based black pigment microparticles as described in the above embodiment [1] or [2], characterized in that it includes a step of mixing a pigment solution in which a perylene-based black pigment is dissolved and a precipitation solvent for precipitating the perylene-based black pigment microparticles from the pigment solution to produce the perylene-based black pigment microparticles;

[0021] Wherein, at least one of the pigment solution and the precipitation solvent independently contains an alkaline earth metal salt and / or a particle growth inhibitor.

[0022] [4] A fourth embodiment of the present invention is a method for producing perylene-based black pigment particles as described in the embodiment of [3] above, characterized in that the alkaline earth metal is calcium.

[0023] [5] Embodiment 5 of the present invention is a method for producing perylene-based black pigment microparticles as described in embodiment [3] or [4] above, characterized in that the pigment solution and the precipitation solvent are mixed in a thin film fluid formed by introducing them between at least two processing surfaces, wherein the at least two processing surfaces are arranged relative to each other to be approachable and separable, and at least one of them rotates relative to the other.

[0024] [6] A sixth embodiment of the present invention is a black pigment composition, characterized in that it contains the perylene-based black pigment fine particles described in the above embodiment [1] or [2].

[0025] [7] Embodiment 7 of the present invention is a method for producing perylene-based black pigment microparticles with controlled hue and / or chromaticity or a black pigment composition containing the perylene-based black pigment microparticles with controlled hue and / or chromaticity, characterized in that the perylene-based black pigment microparticles described in the above embodiment [1] or [2] or the black pigment composition described in the above embodiment [6] are heat-treated to produce the perylene-based black pigment microparticles.

[0026] [8] Embodiment 8 of the present invention is a method for producing perylene-based black pigment microparticles or a black pigment composition containing the perylene-based black pigment microparticles as described in embodiment [7] above, characterized in that the hue and / or chromaticity is controlled by controlling the time and / or temperature of the heat treatment.

[0027] Effects of the Invention

[0028] By using the perylene-based black pigment microparticles of the present invention, the hue and / or chromaticity can be controlled by changing the conditions for heat treatment, and a perylene-based black pigment having high hiding power and light-shielding property and controlled hue and chromaticity can be produced, thereby meeting the market requirements for display quality of display devices.

[0029] The perylene-based black pigment microparticles with controlled hue and / or chromaticity can be used in various applications requiring high hiding power and light-shielding properties, such as inks, coatings, inkjet inks, toners for electrophotography, coloring pigments for rubber and plastics, and further used in black matrices and black columnar spacers for liquid crystal color filters requiring high resistance values.

[0030] Furthermore, the perylene-based black pigment fine particles of the present invention for producing perylene-based black pigment fine particles with controlled hue and / or chromaticity can be produced by a relatively simple treatment of adding an alkaline earth metal salt and / or a particle growth inhibitor. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 FIG. 1 is a transmission electron microscope (TEM) image showing the perylene-based black pigment fine particles of Example 1. FIG.

[0032] Figure 2 FIG. 1 is a transmission electron microscope (TEM) image showing the perylene-based black pigment fine particles of Comparative Example 1. FIG.

[0033] Figure 3 This is a graph showing the measurement results of X-ray diffraction of the perylene-based black pigment fine particles of Example 1.

[0034] Figure 4 It means that the a shown in Table 3 * and b * A diagram showing the CIE-Lab color system chromaticity diagram. DETAILED DESCRIPTION

[0035] 1. Perylene-based black pigment particles

[0036] The perylene-based black pigment fine particles of the present invention are characterized in that they have an average circularity of 0.8 or more and are amorphous fine particles.

[0037] Perylene black pigments used in the present invention include black pigments having a perylene skeleton, and specifically, for example, perylene black pigments described in Patent Document 1 and JP-A-2007-522297, etc. Preferred perylene black pigments include commercially available and widely used perylene imide black pigments, such as CI Pigment Black 31 and CI Pigment Black 32.

[0038] The circularity is measured by approximating the microparticles to an ellipse in the microparticle image and using the major axis (A), perimeter (L) and area (S) of the ellipse as described below. If the microparticles are completely spherical, the circularity is 1. The average circularity of the perylene-based black pigment microparticles of the present invention is 0.8 or more, preferably 0.85 or more, and more preferably 0.9 or more.

[0039] Since the average circularity of the perylene-based black pigment microparticles of the present invention is above 0.8 and close to a sphere, the distance between each microparticle is uniform, gaps are not easily generated between the microparticles, and the hiding power is high. In addition, in the present invention, the circularity of all microparticles does not have to be within the above range, as long as the circularity as the average value is within the above range.

[0040] The crystallinity of the perylene-based black pigment particles can be confirmed by X-ray diffraction (XRD) measurement described below. Amorphous means that no peak is observed in the X-ray diffraction measurement. For example, Figure 3 As a result of X-ray diffraction measurement of the perylene-based black pigment fine particles of Example 1 shown in , no peak was observed, so it was judged to be amorphous.

[0041] From the viewpoint of providing a black pigment composition having dense filling, high hiding power and strong light-shielding property, the average primary particle size of the perylene-based black pigment microparticles of the present invention is preferably 80 nm or less, and from the viewpoint of the ease of pigment dispersion, it is preferably 5 nm or more. More preferably, the average primary particle size is in the range of 10 to 70 nm, further preferably in the range of 20 to 60 nm, and particularly preferably in the range of 30 to 55 nm. When the average primary particle size is within the above range, the filling of the perylene-based black pigment microparticles becomes denser, the hiding power is further improved, and a black pigment composition with higher light-shielding property can be provided. In addition, in the present invention, the primary particle sizes of all microparticles do not have to be within the above range, as long as the average primary particle size as an average value is within the above range.

[0042] 2. Method for producing perylene-based black pigment microparticles

[0043] The method for producing perylene-based black pigment microparticles of the present invention is characterized in that it includes a step of mixing a pigment solution in which a perylene-based black pigment is dissolved and a precipitation solvent for precipitating the perylene-based black pigment microparticles from the pigment solution to generate the perylene-based black pigment microparticles; wherein at least one of the pigment solution and the precipitation solvent independently contains a salt of an alkaline earth metal and / or a particle growth inhibitor.

[0044] Examples of the pigment solution in which the perylene-based black pigment is dissolved include a solution in which the perylene-based black pigment is dissolved in an aprotic organic solvent in the presence of a base.

[0045] As the aprotic organic solvent, any solvent that dissolves the perylene-based black pigment can be used. Specifically, for example, N-methylpyrrolidone, dimethylformamide, N,N-dimethylacetamide, dimethylimidazolidinone, dimethyl sulfoxide, sulfolane, acetone or acetonitrile, tetrahydrofuran, γ-butyrolactone, etc., preferably N-methylpyrrolidone, etc. These solvents can be used alone or in combination of two or more.

[0046] As the base for solubilizing the perylene-based black pigment, any base that can achieve the purpose of the present invention can be used. Specifically, for example, alkali metal hydroxides, alkali metal alkoxides, alkaline earth metal hydroxides, alkaline earth metal alkoxides, quaternary ammonium hydroxides, etc. are listed. Preferably, quaternary ammonium hydroxides such as benzyltrimethylammonium hydroxide are listed, and for example, those that are commercially available in the form of methanol solutions and the like and are easy to handle can be appropriately used. These bases can be used alone or in combination of two or more.

[0047] The concentration of the perylene-based black pigment in the pigment solution is, for example, 0.2 to 10% by weight, preferably 0.5 to 5% by weight, and more preferably 1 to 3% by weight.

[0048] As a precipitation solvent for precipitating perylene-based black pigment microparticles from a pigment solution, for example, a solvent with low solubility of perylene-based black pigment can be cited. Specifically, for example, aqueous solvents such as water, a mixed solvent of a hydrophilic organic solvent and water, and a mixed solvent of an organic solvent miscible with water and water can be cited. As a hydrophilic organic solvent, for example, alcohols such as methanol, ethanol, and ethylene glycol, ketones such as acetone, sulfoxides such as dimethyl sulfoxide, amides such as dimethylformamide and dimethylacetamide, carboxylic acids such as acetic acid can be cited. Alcohols such as methanol, ethanol, and ethylene glycol are preferably cited. As an organic solvent miscible with water, for example, nitriles such as acetonitrile, ethers such as tetrahydrofuran and dimethoxyethane can be cited. The preferred precipitation solvent is water. As needed, a dispersant or acid for neutralizing the alkali can be dissolved in the precipitation solvent. For example, when water alone is not enough to uniformly dissolve a dispersant, or when water alone is not enough to obtain the viscosity required for circulation in the flow path, an organic solvent can be added.

[0049] The volume ratio of the pigment solution to the precipitation solvent during mixing can be appropriately changed and adjusted according to the concentration of the perylene-based black pigment in the pigment solution and the solubility of the perylene-based black pigment in the mixed solution of the precipitation solvent and the pigment solution. The volume ratio of the pigment solution to the precipitation solvent is, for example, 1:100 to 1:1, preferably 1:40 to 1:2, more preferably 1:20 to 1:4, and further preferably 1:15 to 1:5.

[0050] At least one of the pigment solution and the precipitation solvent contains an alkaline earth metal salt and / or a particle growth inhibitor. As described in the comparative examples described below, when neither the alkaline earth metal salt nor the particle growth inhibitor is added, the precipitated perylene-based black pigment microparticles have a circularity as low as about 0.5 and a large particle size.

[0051] As salts of alkaline earth metals, specifically, salts of calcium, magnesium, strontium, etc. can be cited, preferably calcium salts. As salts, inorganic salts such as nitrates, hydrochlorides and sulfates, and organic acid salts such as acetic acid and methanesulfonic acid can be cited. As described in Comparative Examples 2 and 3 described later, when an alkali metal salt such as sodium nitrate or potassium nitrate is added, the circularity of the precipitated perylene-based black pigment microparticles is as low as about 0.5, and the particle size is also large. However, as described in Examples 1 to 8 described later, when an alkaline earth metal salt is added, the circularity of the precipitated perylene-based black pigment microparticles is above 0.85, and the particle size can also be below 80nm. Therefore, by adding alkaline earth metal salts, the circularity of the perylene-based black pigment microparticles can be significantly improved, and the particle size of the microparticles can be significantly reduced.

[0052] The salt of alkaline earth metal can be added to any one or both of the pigment solution and the precipitation solvent. Preferably, it is added to the precipitation solvent. When the salt of alkaline earth metal is added to the precipitation solvent, the concentration of the salt of alkaline earth metal in the precipitation solvent can be, for example, 0.05 to 5% by weight, preferably 0.1 to 2% by weight, and more preferably 0.2 to 1% by weight.

[0053] The particle growth inhibitor is a compound having a hydrophobic group and a hydrophilic group, which has affinity for the carbon skeleton of the perylene-based black pigment molecule and has a hydrophobic group that reduces the growth rate during precipitation and a hydrophilic group that stabilizes the pigment microparticles in the precipitation solvent.

[0054] Preferred examples of hydrophobic groups that have affinity for the carbon skeleton of the perylene-based black pigment molecule and reduce the growth rate during precipitation include aliphatic groups, aryl groups, etc. The aliphatic part of the aliphatic group is linear, branched or cyclic, and may be saturated or unsaturated, for example, it may also contain an alkyl, alkenyl, cycloalkyl or cycloalkenyl group, and may be unsubstituted or substituted by a substituent. In addition, the aryl group may be any of a monocyclic ring and a condensed ring, for example, including phenyl and naphthyl, and may be unsubstituted or substituted by a substituent.

[0055] As the hydrophilic group for stabilizing the pigment fine particles in the precipitation solvent, any group can be used as long as the object of the present invention can be achieved, and preferred examples include an amino group, an ammonium group, a hydroxyl group, a carboxyl group, or a conjugate base thereof.

[0056] Specifically, for example, there can be listed: aliphatic amines such as alkylamines having 6 to 20 carbon atoms, such as octylamine and hexadecylamine; unsaturated aliphatic amines such as alkenylamines having 6 to 20 carbon atoms, such as oleylamine; alkyltrimethylammonium salts having 6 to 20 carbon atoms, such as hexadecyltrimethylammonium salt; quaternary ammonium salts such as benzyltrimethylammonium salt; aliphatic alcohols such as alkanols having 6 to 20 carbon atoms, such as octanol and hexadecyl alcohol; and fatty acid salts such as alkanoates having 6 to 20 carbon atoms, such as sodium laurate and sodium myristate.

[0057] The hydrophilic group may be a group that changes into a hydrophilic structure by a chemical reaction such as hydrolysis. Specific examples of particle growth inhibitors include silane coupling agents such as alkylalkoxysilane and arylalkoxysilane, for example, dodecyltrimethoxysilane and trimethoxyphenylsilane.

[0058] As described in Examples 9 to 16 described later, when a particle growth inhibitor is added, the circularity of the precipitated perylene-based black pigment particles is 0.88 or more, and the particle size can be 80 nm or less. Therefore, by adding a particle growth inhibitor in this way, the circularity of the perylene-based black pigment particles can be significantly improved, and the particle size of the particles can be significantly reduced.

[0059] The particle growth inhibitor may be added to one or both of the pigment solution and the precipitation solvent. It is preferably added to the pigment solution. When the particle growth inhibitor is added to the pigment solution, the concentration of the particle growth inhibitor in the pigment solution may be, for example, 0.01 to 5% by weight, preferably 0.05 to 2% by weight, and more preferably 0.1 to 1% by weight.

[0060] Preferably, pigment solution and the solvent for separating out are imported into at least two processing thin film fluids formed between the faces and mixed, wherein the above-mentioned at least two processing faces are configured to be accessible and separate relative to each other, and wherein at least one rotates relative to another. More specifically, the forced thin film type microreactor manufactured by M Technology Co., Ltd. as shown in Japanese Patent Publication 2010-189661 can be used.

[0061] The precipitation conditions of the perylene-based black pigment microparticles are not particularly limited. As the pressure during precipitation, for example, a range from normal pressure to subcritical and supercritical conditions can be selected. In addition, as the temperature, for example, -30°C to 100°C, preferably -10°C to 60°C, and more preferably 0°C to 30°C. The concentration of the perylene-based black pigment microparticles in the mixed solution after precipitation is not particularly limited. For example, relative to 1000mL of the mixed solution, the perylene-based black pigment microparticles are in the range of 10mg to 40000mg, preferably in the range of 50mg to 20000mg, and more preferably in the range of 100mg to 10000mg.

[0062] 3. Black pigment composition

[0063] The perylene-based black pigment microparticles of the present invention can be used in combination with a black pigment composition. The other components contained in the black pigment composition vary depending on the purpose of the black pigment composition used, and components commonly used in various applications can be cited. In addition, the black pigment composition can be manufactured by mixing these components according to conventional methods. As specific applications, for example, inks, coatings, inkjet inks, toners for electrophotography, coloring pigments for rubber and plastics, and black matrices and black columnar spacers for liquid crystal color filters that require high resistance values ​​can be cited.

[0064] 4. Method for producing perylene-based black pigment microparticles with controlled hue and / or chromaticity

[0065] By heat-treating the perylene-based black pigment particles of the present invention or the black pigment composition containing the perylene-based black pigment particles of the present invention, perylene-based black pigment particles having a controlled hue and / or chromaticity or a black pigment composition containing the perylene-based black pigment particles can be produced.

[0066] For example, by heat-treating the perylene-based black pigment microparticles of the present invention in the state of suspension, the crystallization of amorphous perylene-based black pigment microparticles is promoted, thereby the hue and / or chromaticity thereof can be adjusted. The solvent used to form the suspension can be, for example, water, and in order to suppress the agglomeration of the perylene-based black pigment microparticles, ion exchange water from which salts have been preferably removed is preferably used. In the heat treatment, it is preferably treated by coexisting in water a substance such as a surfactant that can be adsorbed on the surface of the perylene-based black pigment microparticles and used as a protective agent. Agglomeration and particle growth can be suppressed by these substances.

[0067] As the temperature of the heat treatment, it can be appropriately selected according to the target hue and / or chromaticity, but it is preferably treated at a temperature above the boiling point of water by using a sealed can such as an autoclave. As a specific temperature, for example, it can be 100°C to 400°C, preferably 120°C to 300°C, and more preferably 150°C to 250°C. In addition, as the time of the heat treatment, it can be appropriately selected according to the target hue and / or chromaticity, for example, it can be 10 minutes to 5 hours, preferably 20 minutes to 2 hours, and more preferably 30 minutes to 1.5 hours. As described in the embodiments described later, by performing a heat treatment at 150°C to 200°C for 1 hour, the hue and / or chromaticity can be significantly adjusted. In Patent Document 1, the blackness and tinting strength did not change when the heat treatment was performed at 500°C for 1 hour, so the effect of the heat treatment in the present invention is unpredictable by those skilled in the art and has a significant effect.

[0068] Although the heat treatment of the perylene-based black pigment particles of the present invention has been described above, the hue and / or chromaticity of the black pigment composition containing the perylene-based black pigment particles of the present invention can be controlled by subjecting the black pigment composition containing the perylene-based black pigment particles of the present invention to the same heat treatment.

[0069] 5. Perylene-based black pigment microparticles with controlled hue and / or chromaticity

[0070] The perylene-based black pigment microparticles with controlled hue and / or chromaticity produced in the above 4 can be used as a black pigment composition by mixing with a black pigment composition. In addition, the black pigment composition containing the perylene-based black pigment microparticles with controlled hue and / or chromaticity produced in the above 4 can be used as a black pigment composition as it is.

[0071] The other components contained in the black pigment composition vary according to the purpose of the black pigment composition used, and components commonly used in various applications can be cited. In addition, the black pigment composition can be manufactured by mixing these components according to a conventional method. As specific applications, for example, ink, coating, inkjet ink, electrophotographic toner, rubber and plastic coloring pigments, and black matrix and black columnar spacers for liquid crystal color filters requiring high resistance values ​​can be cited.

[0072] 6. Method for controlling the hue and / or chromaticity of perylene-based black pigment particles

[0073] According to the present invention, there is provided a method for controlling the hue and / or chromaticity of perylene-based black pigment fine particles by heat-treating amorphous perylene-based black pigment fine particles.

[0074] As the amorphous perylene-based black pigment fine particles to be heat-treated, those having an average circularity of 0.8 or more and an average primary particle size of 80 nm or less are preferred.

[0075] Heat treatment is as described above. By performing heat treatment in the same manner as described above, the hue and / or chromaticity of the perylene-based black pigment fine particles can be controlled.

[0076] Example

[0077] Hereinafter, the present invention will be further specifically described by way of Examples and Comparative Examples, but the present invention is not limited to these Examples.

[0078] Unless otherwise specified, the following "parts" and "%" are by mass.

[0079] [Measurement of particle size and circularity]

[0080] The particle size and circularity of the perylene-based black pigment fine particles in Examples and Comparative Examples were determined by transmission electron microscope (TEM) observation as follows.

[0081] The pigment particle dispersion was dropped onto a screen with a support film, and the dried pigment particles were used as a sample, and a transmission electron microscope JEM-2100 (manufactured by JEOL Ltd.) was used to observe at an accelerating voltage of 80 kV. Then, 100 particles were selected from the 50,000-fold image, and each particle was approximated as an ellipse using TEM image analysis software iTEM (manufactured by Olympus SoftImaging Solutions GmbH). Next, according to the analysis results of the TEM image analysis software, the major axis (A), perimeter (L) and area (S) of the ellipse as the projection image of the pigment particles were obtained.

[0082] At this time, as described above, since the dispersion is dried on the screen with the support film, even if the perylene-based black pigment particles in the dispersion are in a well-dispersed state, they will aggregate during the drying process, making it difficult to correctly determine the shape of the particles. In this case, image analysis was performed on 100 independent particles that did not overlap.

[0083] The average value of the major axis (A) of the ellipse was calculated for the 100 particles whose images were taken, and this was used as the average primary particle size.

[0084] The circularity is a value calculated by approximating the projection image of a certain pigment particle to an ellipse and using the perimeter (L) and area (S) of the approximate ellipse using formula (1). The closer the circularity value is to 1, the closer the particle is to a sphere. When the particle shape is a true sphere, the maximum circularity is 1.

[0085] Circularity = 4πS / L 2 (1)

[0086] The average circularity of 100 particles of the captured image was calculated and the average circularity was defined as the average circularity.

[0087] Crystallinity determination

[0088] The crystallinity of the perylene-based black pigment fine particles in Examples and Comparative Examples was confirmed by X-ray diffraction (XRD) measurement as follows.

[0089] The dried powder of the perylene-based black pigment particles was used as a sample, and the powder X-ray diffraction measuring device EMPYREAN (manufactured by the PANalytical Division of Spectris Co., Ltd.) was used, and CuKα rays were used as the X-ray source, and the measurement range was 5 to 60°2θ. In the X-ray diffraction measurement, when peak scattering occurs in the test sample, the standard sample is measured under the same conditions as the test sample, and the peak position and half-value width are determined from each X-ray diffraction pattern by using the powder X-ray diffraction comprehensive software HighScorePlus (manufactured by the PANalytical Division of Spectris Co., Ltd.), and the crystallite size is determined by the analysis program of the Scherrer equation.

[0090] [Determination of reflectance spectrum (%R), hue H, chromaticity C and optical density OD]

[0091] The dried powder of the perylene-based black pigment particles of Examples and Comparative Examples was used as a sample, and the reflectance spectrum (%R) was measured in the measurement range of 200 nm to 2500 nm using an ultraviolet-visible-near-infrared spectrophotometer V-770 (manufactured by JASCO Corporation) with an integrating sphere unit.

[0092] The hue and chromaticity of the perylene-based black pigment fine particles in Examples and Comparative Examples were determined as follows using the measurement results of the reflectance spectrum (%R).

[0093] The color values ​​in the CIE-Lab colorimetric system and the CIE-XYZ colorimetric system were obtained from the measurement results using the measurement and analysis software Spectrum Manager Ver.2 Spectrum Analysis (manufactured by JASCO Corporation). The hue, chromaticity, and optical density were calculated using the following equations (2), (3), and (4) using the obtained color values ​​in the CIE-Lab colorimetric system and the CIE-XYZ colorimetric system. In addition, the color values ​​in the CIE-Lab colorimetric system are referred to as “L * a * b * value".

[0094] Hue H = b * / a * (2)

[0095] Chroma C = ((a * ) 2 +(b * ) 2 ) 1 / 2 (3)

[0096] Optical density OD = log(100 / Y) (4)

[0097] First, based on Examples 1 to 8, the case where an alkaline earth metal salt is added to precipitate perylene-based black pigment fine particles will be described.

[0098] <Example 1>

[0099] 15 parts of CI Pigment Black 31 perylene black pigment were suspended in 960 parts of N-methyl-2-pyrrolidone (manufactured by Kishida Chemical Co., Ltd.) in an air atmosphere at 25°C. Then, 25 parts of a 40% methanol solution of benzyltrimethylammonium hydroxide (manufactured by Tokyo Chemical Industry Co., Ltd.) were added to dissolve the perylene black pigment to prepare a pigment solution (1). 50 parts of calcium nitrate tetrahydrate (manufactured by Kanto Chemical Co., Ltd.) were dissolved in 9950 parts of ion exchange water in an air atmosphere at 25°C to prepare a precipitation solvent (1) for precipitating perylene black pigment particles.

[0100] Using a forced thin film microreactor ULREA (manufactured by M Technology Co., Ltd.), a precipitation solvent (1) as a first fluid and a pigment solution (1) as a second fluid were introduced into a disc rotating at 1700 rpm at a flow rate of 300 mL / min and mixed to obtain a suspension containing perylene-based black pigment particles. In each embodiment, the first fluid and the second fluid are the same as the fluids described in the above-mentioned Japanese Patent Publication No. 2010-189661.

[0101] The perylene pigment particles contained in the suspension were filtered and collected by using hard filter paper (pore size 1 μm) under reduced pressure, and washed 3 times with ion exchange water to obtain a wet cake of perylene black pigment particles. The dispersant Neogen RK (manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) was dissolved in ion exchange water, and the wet cake of perylene black pigment particles obtained after washing was dispersed in the solution, and ultrasonic waves were irradiated for 15 minutes using an ultrasonic homogenizer GSD50CF (manufactured by Ginsen Co., Ltd.) to prepare a pigment particle dispersion.

[0102] The wet cake of the perylene-based black pigment fine particles which was not used for preparing the dispersion was dried under reduced pressure at -0.1 MPaG to obtain a dry powder.

[0103] <Example 2>

[0104] Using a forced thin film microreactor ULREA (manufactured by M Technology Co., Ltd.), the same precipitation solvent (1) as in Example 1 as the first fluid was introduced at a flow rate of 500 mL / min, and the same pigment solution (1) as in Example 1 as the second fluid was introduced at a flow rate of 100 mL / min between disks rotating at 5000 rpm and mixed to obtain a suspension containing perylene-based black pigment microparticles. Except for the above operation, the other operations were performed in the same manner as in Example 1.

[0105] <Example 3>

[0106] Under an air atmosphere of 25°C, 20 parts of calcium sulfate dihydrate (manufactured by Kanto Chemical Co., Ltd.) were dissolved in 9980 parts of ion exchange water to prepare a precipitation solvent (2) for precipitating perylene-based black pigment microparticles. Using a forced thin film microreactor ULREA (manufactured by M Technology Co., Ltd.), the precipitation solvent (2) as the first fluid and the pigment solution (1) as the second fluid, which was the same as in Example 1, were introduced into the discs rotating at 1700 rpm and mixed to obtain a suspension containing perylene-based black pigment microparticles. Except for the above-mentioned operation, the other operations were performed in the same manner as in Example 1.

[0107] <Example 4>

[0108] Under an air atmosphere of 25° C., 37 parts of calcium acetate monohydrate (manufactured by Kanto Chemical Co., Ltd.) were dissolved in 9963 parts of ion exchange water to prepare a precipitation solvent (3) for precipitating perylene-based black pigment microparticles. Using a forced thin film microreactor ULREA (manufactured by M Technology Co., Ltd.), the precipitation solvent (3) as the first fluid and the pigment solution (1) as the second fluid, which was the same as in Example 1, were introduced into the discs rotating at 1700 rpm and mixed at a flow rate of 300 mL / min, respectively, to obtain a suspension containing perylene-based black pigment microparticles. Except for the above operation, the other operations were performed in the same manner as in Example 1.

[0109] <Example 5>

[0110] In an air atmosphere at 25°C, 24 parts of calcium chloride (manufactured by Kanto Chemical Co., Ltd.) were dissolved in 9976 parts of ion exchange water to prepare a precipitation solvent (4) for precipitating perylene-based black pigment microparticles. Using a forced thin film microreactor ULREA (manufactured by M Technology Co., Ltd.), the precipitation solvent (4) as the first fluid and the pigment solution (1) as the second fluid, which was the same as in Example 1, were introduced into the discs rotating at 1700 rpm and mixed at a flow rate of 300 mL / min, respectively, to obtain a suspension containing perylene-based black pigment microparticles. Except for the above operation, the other operations were performed in the same manner as in Example 1.

[0111] <Example 6>

[0112] In an air atmosphere at 25°C, 50 parts of calcium nitrate tetrahydrate (manufactured by Kanto Chemical Co., Ltd.) and 13 parts of 60% nitric acid (manufactured by Kanto Chemical Co., Ltd.) were dissolved in 9937 parts of ion exchange water to prepare a precipitation solvent (5) for precipitating perylene-based black pigment microparticles. Using a forced thin film microreactor ULREA (manufactured by M Technology Co., Ltd.), the precipitation solvent (5) as the first fluid and the pigment solution (1) as the second fluid as in Example 1 were introduced into the discs rotating at 1700 rpm at a flow rate of 300 mL / min and mixed to obtain a suspension containing perylene-based black pigment microparticles. Except for the above operation, the other operations were carried out in the same manner as in Example 1.

[0113] <Example 7>

[0114] In an air atmosphere at 25°C, 54 parts of magnesium nitrate hexahydrate (manufactured by Kanto Chemical Co., Ltd.) and 13 parts of 60% nitric acid (manufactured by Kanto Chemical Co., Ltd.) were dissolved in 9933 parts of ion exchange water to prepare a precipitation solvent (6) for precipitating perylene-based black pigment microparticles. Using a forced thin film microreactor ULREA (manufactured by M Technology Co., Ltd.), the precipitation solvent (6) as the first fluid and the pigment solution (1) as the second fluid as in Example 1 were introduced into the discs rotating at 1700 rpm at a flow rate of 300 mL / min and mixed to obtain a suspension containing perylene-based black pigment microparticles. Except for the above operation, the other operations were carried out in the same manner as in Example 1.

[0115] <Example 8>

[0116] In an air atmosphere at 25°C, 45 parts of strontium nitrate (manufactured by Kanto Chemical Co., Ltd.) and 13 parts of 60% nitric acid (manufactured by Kanto Chemical Co., Ltd.) were dissolved in 9942 parts of ion exchange water to prepare a precipitation solvent (7) for precipitating perylene-based black pigment microparticles. Using a forced thin film microreactor ULREA (manufactured by M Technology Co., Ltd.), the precipitation solvent (7) as the first fluid and the pigment solution (1) as the second fluid, which was the same as in Example 1, were introduced into a disk rotating at 1700 rpm and mixed at a flow rate of 300 mL / min, respectively, to obtain a suspension containing perylene-based black pigment microparticles. Except for the above operation, the other operations were performed in the same manner as in Example 1.

[0117] <Comparative Example 1>

[0118] Using a forced thin film microreactor ULREA (manufactured by M Technology Co., Ltd.), ion exchange water as the first fluid and the pigment solution (1) as the second fluid as in Example 1 were introduced at a flow rate of 300 mL / min between disks rotating at 1700 rpm and mixed to obtain a suspension containing perylene-based black pigment particles. Except for the above operation, the other operations were carried out in the same manner as in Example 1.

[0119] <Comparative Example 2>

[0120] In an air atmosphere at 25°C, 36 parts of sodium nitrate (manufactured by Kanto Chemical Co., Ltd.) were dissolved in 9964 parts of ion exchange water to prepare a precipitation solvent (8) for precipitating perylene-based black pigment microparticles. Using a forced thin film microreactor ULREA (manufactured by M Technology Co., Ltd.), the precipitation solvent (8) as the first fluid and the pigment solution (1) as the second fluid, which was the same as in Example 1, were introduced into the discs rotating at 1700 rpm at a flow rate of 300 mL / min and mixed to obtain a suspension containing perylene-based black pigment microparticles. Except for the above operation, the other operations were performed in the same manner as in Example 1.

[0121] <Comparative Example 3>

[0122] In an air atmosphere at 25°C, 43 parts of potassium nitrate (manufactured by Kanto Chemical Co., Ltd.) was dissolved in 9957 parts of ion exchange water to prepare a precipitation solvent (9) for precipitating perylene-based black pigment microparticles. Using a forced thin film microreactor ULREA (manufactured by M Technology Co., Ltd.), the precipitation solvent (9) as the first fluid and the pigment solution (1) as the second fluid as in Example 1 were introduced into the discs rotating at 1700 rpm at a flow rate of 300 mL / min and mixed to obtain a suspension containing perylene-based black pigment microparticles. Except for the above operation, the other operations were performed in the same manner as in Example 1.

[0123] The particle size and circularity of the perylene-based black pigment microparticles prepared in each embodiment and comparative example were confirmed by transmission electron microscopy (TEM). It can be clearly seen from the results in Table 1 that when the alkaline earth metal salt is coexisted in the particle preparation process of the present invention, approximately spherical perylene-based black pigment microparticles can be obtained.

[0124] Table 1

[0125]

[0126] Next, based on Examples 9 to 16, the case where a particle growth inhibitor is added to precipitate perylene-based black pigment fine particles will be described.

[0127] <Example 9>

[0128] 15 parts of CI Pigment Black 31 perylene-based black pigment were suspended in 955 parts of N-methyl-2-pyrrolidone (manufactured by Kishida Chemical Co., Ltd.) in an air atmosphere at 25° C. Then, 25 parts of a 40% methanol solution of benzyltrimethylammonium hydroxide (manufactured by Tokyo Chemical Industry Co., Ltd.) and 5 parts of octylamine were added to dissolve the perylene-based black pigment, thereby preparing a pigment solution (2).

[0129] Using a forced thin film microreactor ULREA (manufactured by M Technology Co., Ltd.), ion exchange water as the first fluid and the pigment solution (2) as the second fluid were introduced into the space between the disks rotating at 1700 rpm at a flow rate of 300 mL / min and mixed to obtain a suspension containing perylene-based black pigment particles. Except for the above operation, the other operations were carried out in the same manner as in Example 1.

[0130] <Example 10>

[0131] The same operation as in Example 9 was carried out except that 5 parts of hexadecylamine were used in place of 5 parts of octylamine in the pigment solution (2) of Example 9.

[0132] <Example 11>

[0133] The same operation as in Example 9 was carried out except that 5 parts of oleylamine was used in place of 5 parts of octylamine in the pigment solution (2) of Example 9.

[0134] <Example 12>

[0135] The same operation as in Example 9 was carried out except that 5 parts of hexadecyltrimethylammonium bromide was used in place of 5 parts of octylamine in the pigment solution (2) of Example 9.

[0136] <Example 13>

[0137] The same operation as in Example 9 was carried out except that 5 parts of octanol were used in place of 5 parts of octylamine in the pigment solution (2) of Example 9.

[0138] <Example 14>

[0139] The same operation as in Example 9 was carried out except that 5 parts of hexadecanol were used in place of 5 parts of octylamine in the pigment solution (2) of Example 9.

[0140] <Example 15>

[0141] The same operation as in Example 9 was carried out except that 5 parts of dodecyltrimethoxysilane was used in place of 5 parts of octylamine in the pigment solution (2) of Example 9.

[0142] <Example 16>

[0143] The same operation as in Example 9 was carried out except that 5 parts of trimethoxyphenylsilane was used in place of 5 parts of octylamine in the pigment solution (2) of Example 9.

[0144] The particle size and circularity of the perylene-based black pigment fine particles prepared in Examples 9 to 16 were confirmed by transmission electron microscopy (TEM). As is clear from the results in Table 2, when a particle growth inhibitor is allowed to coexist in the particle preparation process of the present invention, approximately spherical perylene-based black pigment fine particles can be obtained.

[0145] Table 2

[0146]

[0147] As a representative example, the TEM images of Example 1 and Comparative Example 1 are shown in Figure 1 and Figure 2 middle.

[0148] The crystallinity of the perylene-based black pigment microparticles produced in each embodiment and comparative example was confirmed by X-ray diffraction (XRD) measurement. As a result of the X-ray diffraction measurement, only a halo diffraction image was confirmed in the dry powder of the perylene-based black pigment microparticles produced in each embodiment, and the powder was amorphous. As a result of the X-ray diffraction measurement, a broad diffraction pattern was confirmed in the dry powder of the perylene-based black pigment microparticles produced in the comparative example.

[0149] <Heat-treated crystallization of perylene-based black pigment particles>

[0150] The dried powder of the perylene-based black pigment particles prepared in Example 2 was suspended in ion exchange water and sealed in an autoclave, and heat-treated at 150° C., 175° C., and 200° C. for 1 hour using a thermostatic bath AVO-250N (manufactured by AS ONE Co., Ltd.). The heat-treated suspension was centrifuged to separate a wet cake containing the perylene-based black pigment particles, which was then dried under reduced pressure at -0.1 MPaG to obtain a dried powder.

[0151] The dried powder of the perylene-based black pigment particles obtained after drying was used as a sample for X-ray diffraction measurement to calculate the crystallite size. The X-ray diffraction pattern of crystals appeared by heat treatment, and as the treatment temperature increased, the X-ray diffraction pattern became sharper and the crystallite size increased (Table 3).

[0152] <Controlling the Hue and / or Chroma of Perylene-Based Black Pigment Particles by Heat Treatment>

[0153] The reflectance spectrum (%R) of the perylene-based black pigment fine particles obtained by each heat treatment was measured, and the hue, chromaticity, and optical density were confirmed.

[0154] Table 3 shows the crystallite size, L * a * b * From the results in Table 3, it can be seen that when the perylene-based black pigment particles obtained in the present invention are heat-treated, the chromaticity decreases as the treatment temperature increases, and the L * decreases and the optical density increases.

[0155] [Table 3]

[0156] Before heat treatment 150℃ 175℃ 200℃ Crystallite size [nm] - 2.1 3.9 6.4 <![CDATA[L * ]]> 11.94 10.92 9.17 8.98 <![CDATA[ * ]]> 13.34 4.97 4.04 2.77 <![CDATA[b * ]]> 11.02 7.96 5.30 3.72 Hue H 0.83 1.60 1.31 1.34 Chroma C 17.30 9.38 6.66 4.64 Optical density OD 1.85 1.90 1.99 2.00

[0157] The a shown in Table 3 * 、b * The figure marked on the CIE-Lab color system chromaticity diagram is as follows Figure 4The results show that with the increase of heat treatment temperature, b * / a * tends to decrease and approach the origin (a * =0, b * =0).

[0158] Industrial Applicability

[0159] According to the present invention, it is possible to provide perylene-based black pigment microparticles having high hiding power and light-shielding property and controlled hue and chroma, and a method for simply producing the microparticles.

Claims

1. A perylene-based black pigment microparticle, characterized in that: The average circularity is 0.8 or more and the particles are amorphous. The perylene-based black pigment is Pigment Black 31, It is manufactured by the following manufacturing method: The method comprises the steps of mixing a pigment solution in which a perylene-based black pigment is dissolved and a precipitation solvent for precipitating perylene-based black pigment microparticles from the pigment solution to produce perylene-based black pigment microparticles. wherein at least one of the pigment solution and the precipitation solvent independently contains an alkaline earth metal salt and / or a particle growth inhibitor, The particle growth inhibitor is selected from alkylamines with carbon numbers of 6 to 20, alkenylamines with carbon numbers of 6 to 20, alkyltrimethylammonium salts with carbon numbers of 6 to 20, benzyltrimethylammonium salts, alkanols with carbon numbers of 6 to 20, alkanoates with carbon numbers of 6 to 20, alkylalkoxysilanes and arylalkoxysilanes.

2. The perylene-based black pigment microparticles according to claim 1, wherein: The average primary particle size is 80 nm or less.

3. A method for producing perylene-based black pigment particles according to claim 1 or 2, characterized in that: The method comprises the steps of mixing a pigment solution in which a perylene-based black pigment is dissolved and a precipitation solvent for precipitating perylene-based black pigment microparticles from the pigment solution to generate perylene-based black pigment microparticles; wherein at least one of the pigment solution and the precipitation solvent independently contains an alkaline earth metal salt and / or a particle growth inhibitor, The particle growth inhibitor is selected from alkylamines with carbon numbers of 6 to 20, alkenylamines with carbon numbers of 6 to 20, alkyltrimethylammonium salts with carbon numbers of 6 to 20, benzyltrimethylammonium salts, alkanols with carbon numbers of 6 to 20, alkanoates with carbon numbers of 6 to 20, alkylalkoxysilanes and arylalkoxysilanes.

4. The method for producing perylene-based black pigment particles according to claim 3, wherein: The alkaline earth metal is calcium.

5. The method for producing perylene-based black pigment particles according to claim 3 or 4, wherein: The pigment solution and the precipitation solvent are mixed by introducing them into a thin film fluid formed between at least two processing surfaces, wherein the at least two processing surfaces are arranged relative to each other to be accessible and separable, and at least one of them rotates relative to the other.

6. A black pigment composition, characterized in that: The pigment contains the perylene-based black pigment fine particles according to claim 1 or 2.

7. A method for producing perylene-based black pigment microparticles with controlled hue and / or chroma or a black pigment composition containing the perylene-based black pigment microparticles with controlled hue and / or chroma, characterized in that: The method is produced by heat-treating the perylene-based black pigment fine particles according to claim 1 or 2 or the black pigment composition according to claim 6.

8. The method for producing perylene-based black pigment microparticles or a black pigment composition containing the perylene-based black pigment microparticles according to claim 7, characterized in that: The hue and / or chroma can be controlled by controlling the time and / or temperature of the heat treatment.

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