Amine-modified organic pigment and method for producing same

Abstract

[Problem] To obtain an organic pigment which can be easily dispersed in an organic solvent even if a dispersing agent is not added. [Solution] Provided is a method for producing an amine-modified organic pigment, the method being characterized by mixing, in water, an amine compound and a water-dispersible organic pigment having a carboxyl group and / or a sulfone group at a particle surface to bind the amine compound to the organic pigment.

Description

Amine-Modified Organic Pigment and Method for Producing the Same

[0001] The present invention relates to an amine-modified organic pigment and a method for producing the same.

[0002] The use of organic pigments in the industry is widely accepted for multiple applications such as coloring of resins, etc., coloring materials for printing inks and inkjet toners, and members of electronic devices. Generally, organic pigments are extremely fine particles and tend to aggregate, making it difficult to uniformly mix with binders, solvents, and other components.

[0003] Therefore, organic pigments are generally used as a dispersion liquid in a uniformly dispersed state by adding a dispersant such as a so-called polymer resin. However, the dispersant may inhibit the performance of other components depending on the application. In addition, in order to loosen aggregation, it is necessary to apply a shearing force or an impact force, and for this reason, there is also a demerit that a so-called dispersion device such as a bead mill or a roll mill is required. Therefore, various methods have been proposed to prevent aggregation by modifying the surface of organic pigments and to easily disperse them in a dispersion medium without the need for a dispersant.

[0004] For example, as an attempt to increase hydrophilic functional groups on the surface of an organic pigment by an oxidation reaction and disperse it in water, Patent Document 1 describes reacting a phthalocyanine blue pigment, an indigoid pigment, an anthraquinone pigment, a quinacridone pigment, and a diazonium salt as organic pigments to bond a hydrophilic group to the surface of the organic pigment, thereby producing an organic pigment that easily disperses in an aqueous medium. Further, Patent Document 2 describes producing an oxidation-type self-dispersing pigment suitable for use in an aqueous ink by subjecting a magenta pigment as an organic pigment to an oxidation treatment by contacting it with ozone gas. In addition, Non-Patent Document 1 reports a method of sulfonating the surface of a pigment with a sulfonating agent such as sulfuric acid or sulfamic acid in a sulfonating solvent such as sulfolane and then phase-transferring it to an aqueous system. Further, Patent Documents 3, Patent Document 4, Non-Patent Document 2, and Non-Patent Document 3 describe imparting dispersibility in water by coating or encapsulating a pigment with a resin.

[0005] Japanese Patent Publication No. 4138882, Japanese Unexamined Patent Publication No. 2012-117020, Japanese Unexamined Patent Publication No. 2003-253151, Japanese Unexamined Patent Publication No. 2019-056090, Japanese Unexamined Patent Publication No. 2023-153059, Journal of the Image Science Society of Japan, Vol. 41, No. 2 (2002), 174-178, Jun Satake, "Self-dispersing pigment IJ ink," Journal of the Image Science Society of Japan, Vol. 38, No. 3, 195-202 (1999), Kengo Yasui, "Pigment dispersion in pigment ink for inkjet," Journal of the Color Materials Association, 78(9), 422-430 (2005), Kengo Yasui, "High image quality and microencapsulated pigments in inkjet pigment inks."

[0006] However, all of these methods are cumbersome and, since they are intended for dispersion in aqueous media, their dispersibility in organic solvents is insufficient. As mentioned above, organic pigments generally have very few hydrophilic groups on their surface, making dispersion in aqueous inks difficult. In particular, in aqueous inkjet applications, there have been considerations for introducing hydrophilic groups due to stringent requirements such as ensuring nozzle ejection performance. However, the absence of very few hydrophilic groups does not mean that dispersion in hydrophobic media is easy. Although there is at least a potential need to improve performance by eliminating aggregation between pigment particles and uniformly dispersing them in hydrophobic media such as organic solvents, this has been largely ignored, and no solutions have been found. Furthermore, although methods for imparting self-dispersibility in organic solvents to carbon black have been proposed, as in Patent Document 5, the surface conditions of carbon black and organic pigments are different. Carbon black has some reactive functional groups on its surface, while organic pigments have almost none, and the inventors' research has revealed that the methods for carbon black cannot be directly applied.

[0007] Therefore, the inventors diligently studied how to obtain organic pigments that self-disperse in organic solvents, that is, organic pigments that disperse easily in organic solvents without the need for dispersants. As a result, they discovered that organic pigments with a specific surface condition can be easily dispersed in organic solvents by simple mixing without the need for dispersants or dispersion equipment, and they also found a simple method for obtaining such organic pigments, leading to the present invention.

[0008] The present invention provides: (1) A method for producing an amine-modified organic pigment, characterized by mixing a hydrophilic organic pigment having hydrophilic functional groups bonded to its surface with an amine compound in an aqueous medium to bond the amine compound to the organic pigment, wherein the amine compound has an amine value of 10 to 120 mg KOH / g and a weight-average molecular weight of 500 to 50,000, and the equivalent amount of the amine compound is equal to or greater than the equivalent amount of hydrophilic functional groups on the surface of the hydrophilic organic pigment; (2) The method for producing an amine-modified organic pigment according to (1), characterized in that the amine compound is soluble in one or more organic solvents selected from toluene, butyl acetate, and methyl ethyl ketone; (3) The method for producing an amine-modified organic pigment according to (1), characterized in that the amine compound is soluble in propylene glycol monomethyl ether acetate or benzyl acrylate; (4) The method for producing an amine-modified organic pigment according to (1), characterized in that the amine compound and the organic pigment are bonded via one or more of -SO2NH-, -SO2N-, -CONH-, and -CON-; (5) A method for producing an amine-modified organic pigment as described in (1) above, wherein the amine portion of the amine compound is one or more of cyclic imides, oxazolines, or imidazolidinones.

[0009] (6) An amine-modified organic pigment, wherein a hydrophilic functional group is introduced into the organic pigment and the amine compound is bonded to the organic pigment by mixing with the amine compound in an aqueous medium, wherein the amine compound has an amine value of 10 to 120 mg KOH / g and a weight-average molecular weight of 500 to 50,000, and the blending ratio of the organic pigment to the amine compound is 1 to 500 parts by weight of the amine compound in terms of solid content per 100 parts by weight of the organic pigment, (7) An amine-modified organic pigment, wherein the amine compound is bonded to the organic pigment, wherein the amine compound is (i) bonded to the organic pigment via one or more of -SO2NH-, -SO2N-, -CONH-, and -CON-, (ii) has an amine value of 10 to 120 mg KOH / g including the amine value of the bonded portion to the organic pigment, and (iii) is an amine compound with a molecular weight of 500 to 50,000, (8) The amine-modified organic pigment described in (6) or (7) above, characterized in that the amine compound is soluble in one or more organic solvents selected from toluene, butyl acetate, and methyl ethyl ketone; (9) The amine-modified organic pigment described in (6) or (7) above, characterized in that the amine compound is soluble in propylene glycol monomethyl ether acetate or benzyl acrylate; (10) The amine-modified organic pigment described in (6) or (7) above, characterized in that the amine portion of the amine compound is one or more selected from cyclic imide, oxazoline, or imidazolidinone; (11) The amine-modified organic pigment dispersion in which the amine-modified organic pigment described in (6) or (7) above is dispersed in an organic solvent; and (12) A coloring composition containing the amine-modified organic pigment described in (6) or (7) above.

[0010] Figure 1 shows a photograph of the dispersion on a glass plate in "3. Evaluation of dispersibility in ammonia water" for hydrophilic pigment 1. Figure 2 shows a photograph of the dispersion on a glass plate in "3. Evaluation of dispersibility in ammonia water" for hydrophilic pigment 2. Figure 3 shows a photograph of the dispersion on a glass plate in "3. Evaluation of dispersibility in ammonia water" for hydrophilic pigment 3. Figure 4 shows a photograph of the dispersion on a glass plate in "3. Evaluation of dispersibility in ammonia water" for hydrophilic pigment 4. Figure 5 shows a photograph of the dispersion on a glass plate in "3. Evaluation of dispersibility in ammonia water" for hydrophilic pigment 5. Figure 5 shows a photograph of the dispersion on a glass plate in "3. Evaluation of dispersibility in ammonia water" for "HEUCO(R) Blue 501501" before sulfonation or carboxylation in the synthesis example. Figure 65 shows a photograph of the dispersion on a glass plate in "3. Evaluation of dispersibility in ammonia water" for "TONER MAGENTA E" before sulfonation or carboxylation in the synthesis example. The diagram shows a photograph of the dispersion liquid dropped onto a glass plate in the "Evaluation of Dispersibility in Ammonia Water" example. The diagram shows a photograph of the dispersion liquid dropped onto a glass plate in the "3. Evaluation of Dispersibility in Ammonia Water" example, before sulfonation or carboxylation of "Irgalite(R) Blue BSP".

[0011] [Organic Pigments] The amine-modified organic pigments of the present invention are those in which an amine compound is bonded to an organic pigment. Such amine-modified organic pigments of the present invention can be obtained by reacting an amine compound with an organic pigment having a sufficient amount of hydrophilic functional groups on its surface. Generally, organic pigments have almost no hydrophilic functional groups on their surface, so the amine-modified organic pigments of the present invention can be obtained by introducing hydrophilic functional groups into an existing organic pigment to create an organic pigment having hydrophilic functional groups on its surface, and then reacting it with an amine compound. However, any organic pigment that already has a sufficient amount of hydrophilic functional groups on its surface can be used without any problems.

[0012] Organic pigments can be used without particular restrictions. For example, they may be blue, brown, cyan, green, violet, magenta, red, yellow, or mixtures thereof. Suitable structures for organic pigments include, for example, anthraquinone, phthalocyanine blue, phthalocyanine green, diazo, monoazo, pyrantrone, perylene, heterocyclic yellow, quinacridone, and (thio)indigoid. A typical example of phthalocyanine blue is copper phthalocyanine blue and its derivatives (pigment blue 15). Typical examples of quinacridone include pigment orange 48, pigment orange 49, pigment red 122, pigment red 192, pigment red 202, pigment red 206, pigment red 207, pigment red 209, pigment violet 19, and pigment violet 42. Representative examples of anthraquinones include Pigment Red 43, Pigment Red 194 (Perinone Red), Pigment Red 216 (Brominated Pyrantrone Red), and Pigment Red 226 (Pyrantrone Red). Representative examples of pyrerines include Pigment Red 123 (Vermilion), Pigment Red 149 (Scarlet), Pigment Red 179 (Maroon), Pigment Red 190 (Red), Pigment Violet, Pigment Red 189 (Yellow Shade Red), and Pigment Red 224. Representative examples of thioindigoids include Pigment Red 86, Pigment Red 87, Pigment Red 88, Pigment Red 181, Pigment Red 198, Pigment Violet 36, and Pigment Violet 38. Representative examples of heterocyclic yellows include Pigment Yellow 117 and Pigment Yellow 138. In addition, materials described in Patent Document 1, Non-Patent Document 1, etc., and materials described in The Colour Index, Third Edition (The Society of Dyers and Colourists, 1982) may also be used.

[0013] In this invention, an organic pigment having a sufficient amount of hydrophilic functional groups on its surface (hereinafter referred to as "hydrophilic organic pigment") is used and reacted with an amine compound described later. A sufficient amount of hydrophilic functional groups means an amount sufficient for the organic pigment to be uniformly dispersed in an aqueous medium, and can be specifically confirmed by the following method. The type of hydrophilic functional group is not limited here, and acidic functional groups, specifically carboxyl groups and sulfone groups, are typical, but it is not limited to these, and any organic pigment that disperses in water by the following confirmation method is considered a hydrophilic organic pigment having a sufficient amount of hydrophilic functional groups in this invention.

[0014] To prepare the evaluation solution, 1 part by weight of 25% ammonia water and 8 parts by weight of ion-exchanged water are added to 1 part by weight of organic pigment in a 100 ml S-bottle (manufactured by Kokugo Co., Ltd.). 23 g of Sepul ER120S is added, and the mixture is dispersed for 30 minutes using a paint shaker (manufactured by Asada Iron Works Co., Ltd.). The evaluation solution is then dropped onto a glass plate placed on white copy paper using a 2 ml poly dropper (manufactured by AS ONE Corporation). Another 2 ml of ion-exchanged water is then dropped using the poly dropper, and the appearance of the dropped material is observed to visually confirm whether or not liquid separation occurs. Substances that aggregate and separate from the water do not have a sufficient amount of hydrophilic functional groups on the surface. Substances that disperse and become uniform with the water have a sufficient amount of hydrophilic functional groups on the surface and can be used in the following steps in this invention (Figures 6-8 show that the water and organic pigment are separated, while Figures 1-5 show that they are uniformly dispersed). This is referred to as "hydrophilic organic pigment" in this invention.

[0015] As mentioned above, general organic pigments have little to no hydrophilicity on their surface, so in such cases, it is necessary to impart hydrophilic functional groups to them to make them hydrophilic organic pigments. The method of imparting hydrophilic functional groups is not limited, and various known surface modification methods can be used. Typical hydrophilic functional groups include acidic functional groups such as carboxyl groups and sulfone groups, and hydrophilic functional groups can be bonded to organic pigments by oxidizing them using known oxidation methods. More specifically, there are methods such as gas-phase oxidation with ozone, NOx, etc., and liquid-phase oxidation with nitric acid, hydrogen peroxide, ozonated water, iodine water, hypochlorite, chlorite, permanganate, dichromate, peroxodisulfate, etc. For example, oxidation with ozone is described in Patent Document 2. Oxidation with ozone, in particular, can bond a large number of carboxyl groups.

[0016] Furthermore, as described in Patent Document 1, a compound having an amino group and a hydrophilic functional group (such as a sulfone group or carboxyl group) can be used, and the diazonium salt produced by diazotizing the amino group with nitrite can be bonded (diazocoupling) to the surface of the organic pigment, thereby introducing a hydrophilic functional group, such as a sulfone group, to the surface of the organic pigment. When using such a diazo reaction, the organic pigment should not contain a primary amine and, preferably, have at least one aromatic ring in its repeating structure. This promotes the diazocoupling reaction to the surface of the pigment.

[0017] When introducing sulfone groups using a diazo coupling reaction, a typical method involves using diazo compounds of aromatic amines containing sulfone groups, such as sulfanilic acid. Sulfanilic acid is soluble in water at room temperature if the concentration is 2% by weight or less, but it becomes insoluble if the concentration exceeds 2% by weight. However, even if the concentration exceeds 2% by weight, it can be dissolved by adding a basic component. After the diazotization reaction is carried out with sulfanilic acid dissolved in water, contact with an organic pigment can be used to introduce sulfone groups onto the surface of the organic pigment.

[0018] In addition to sulfanilic acid, various sulfonic acid compounds can also be used to introduce sulfonate groups, such as 5-amino-2-hydroxybenzenesulfonic acid, 5-aminobenzenesulfonic acid, 3-aminobenzenesulfonic acid, 4-aminobenzene-4' sulfonic acid, 5-amino-2-naphthalenesulfonic acid, 4-amino-5-hydroxy2,7-naphthalenedisulfonic acid, 7-amino-1,3-naphthalenedisulfonic acid, and 4-amino-1-naphthalenesulfonic acid. However, like sulfanilic acid, it is preferable to use these compounds in a water-soluble state. The amount of sulfonate groups introduced affects the dispersibility of organic pigments in water, and the amount of these sulfonating agents required for dispersion will vary depending on the type of organic pigment (molecular structure, particle size, etc.). For example, in the case of phthalocyanine blue PB15:0, sufficient dispersibility in water can be achieved by introducing sulfonate groups using 3 parts by weight or more of sulfanilic acid per 100 parts by weight of organic pigment.

[0019] On the other hand, excessive oxidation or sulfonation offers no particular advantage, and inorganic salts may be formed from counterions derived from inorganic materials such as sodium nitrite and hydrochloric acid added during the reaction. These can cause poor dispersion or foreign matter when dispersed in organic solvents. For this reason, generally, 1 to 30 parts by weight, preferably 3 to 20 parts by weight, of a sulfonating agent and / or carboxylating agent should be selected per 100 parts by weight of organic pigment. The diazotization reaction can also be used as a method for introducing carboxyl groups. Diazo compounds of 4-aminobenzoic acid or ethyl 4-aminobenzoic acid can also be used. By dissolving 4-aminobenzoic acid, etc., in water, carrying out the diazotization reaction, and then contacting it with the organic pigment, carboxyl groups can be introduced onto the surface of the organic pigment.

[0020] Commercially available hydrophilic organic pigments can also be used. Examples of commercially available products with many hydrophilic functional groups include organic pigments that are sold as so-called self-dispersing pigments, in which hydrophilic functional groups such as carboxyl groups and sulfone groups are introduced to the surface. Specifically, these include CAB-O-JET(R) dispersion 4507C (Cyan / PB 15:4), CAB-O-JET(R) dispersion 4707Y (Yellow / PY74), CAB-O-JET(R) dispersion 4607M (Magenta), CAB-O-JET(R) dispersion 480V (Magenta / PV19), CAB-O-JET(R) dispersion 740Y (Yellow / PY155), and CAB-O-JET(R) 1027R (Red) (all are trade names, manufactured by Cabot Specialty Chemicals Inc.).

[0021] [Amine Compounds] The hydrophilic organic pigment described above is reacted with an amine compound. Specifically, this is a primary amine, a secondary amine, or a cyclic amine. These amine compounds bind to the hydrophilic functional groups on the surface of the hydrophilic organic pigment described above, forming an amine-modified organic pigment that disperses particularly easily in organic solvents. In particular, it is extremely preferable that the amine compound is a primary amine, a secondary amine, or a cyclic amine with an amine value of 10 to 120 mg KOH / g and a molecular weight of 500 to 50,000. Such amine compounds react particularly readily with the hydrophilic functional groups on the surface of the hydrophilic organic pigment described above, forming an amine-modified organic pigment that disperses particularly easily in organic solvents.

[0022] (Amine species) As described above, the amine compounds are primary or secondary amines other than cyclic amines, or cyclic amines, and the cyclic amines are not limited to primary or secondary amines. It is thought that this is due to the substitution and bonding of hydrogen atoms from primary or secondary amines, or hydrogen atoms produced when a cyclic amine opens its ring, with hydrophilic functional groups such as sulfone groups and carboxyl groups of hydrophilic organic pigments. Therefore, cyclic amines that can open their rings and react with hydrophilic functional groups on the surface of hydrophilic organic pigments are preferred, and specific examples include cyclic imides, oxazolines, and imidazolidinones. An example of oxazoline is the Epocross series (product name, manufactured by Nippon Shokubai Co., Ltd.). All of these amines may also be in the form of amine salts that constitute a salt with an organic acid or an inorganic acid.

[0023] (Amine Value) The amine value of the amine compound is preferably 10 to 120 mg KOH / g, and particularly preferably 20 to 110 mg KOH / g. The amine value is measured according to JIS K 7237. In the case of the present invention, the amine value of the amine compound containing the amine salt is the value measured after returning to the amine before neutralization by hydrolysis. If the amine value is too low, there may be insufficient amine to bind to the hydrophilic organic pigment, and the surface of the organic pigment may not be sufficiently modified, which may reduce the dispersibility in organic solvents. If the amine value is too high, the polarity of the amine compound may increase, which may affect the dispersibility in organic solvents.

[0024] (Molecular Weight) The weight-average molecular weight of the amine compound is 500 to 50,000. Preferably, it is 500 to 30,000, more preferably 500 to 20,000, and particularly preferably 1,000 to 20,000. By using an amine compound with a molecular weight within this range, the resulting amine-modified organic pigment disperses easily in an organic solvent. If the molecular weight is too small, the resulting amine-modified organic pigment tends to aggregate in the organic solvent. This is presumed to be because the steric hindrance effect is small due to the small size of the surface-modifying amine compound, resulting in a small interparticle distance of the organic pigment. Conversely, if the molecular weight is too large, the penetration power of the organic solvent decreases, making it difficult to wet and thus difficult to disperse. The weight-average molecular weight here is measured using gel permeation chromatography (GPC). The measurement conditions should be standard conditions for each type of amine compound. (Polystyrene equivalent)

[0025] (Affinity with Organic Solvents) In order for amine-modified organic pigments obtained by reacting hydrophilic organic pigments with amine compounds to disperse easily in organic solvents without the need for dispersants or dispersion equipment, it is preferable that the amine compound has a high affinity for the target organic solvent. As shown in the examples described later, the inventors have confirmed that if an amine compound with affinity for a certain organic solvent is bound to an organic pigment, the organic pigment to which the amine compound is bound disperses easily in that organic solvent. This is presumed to be because when an amine compound with high affinity for a certain organic solvent is bound to it, the molecular chain of the amine compound spreads easily in the organic solvent and acts as steric hindrance between organic pigment particles, increasing the distance between particles, preventing aggregation in the organic solvent, and stabilizing the dispersion state. In the present invention, as described below, a wide range of amine compounds can be selected to be bound to the organic pigment, so by selecting an amine compound that matches the target organic solvent, the amine-modified organic pigment can be dispersed in an organic solvent. More specifically, amine-modified organic pigments that readily disperse in organic solvents such as toluene, butyl acetate, PMA (propylene glycol monomethyl ether acetate), MEK (methyl ethyl ketone), IPA (isopropyl alcohol), NMP (N-methyl-2-pyrrolidone), and BZA (benzyl acrylate, acrylic monomer) can be obtained. To select an amine compound to be used for modification to obtain amine-modified organic pigments that readily disperse in these organic solvents, one should select an amine compound that dissolves in these organic solvents and bond it to the organic pigment using the method of the present invention. In particular, as shown in the examples described later, some amine compounds are soluble in a wide range of organic solvents, so by selecting such an amine compound, organic pigments that readily disperse in a wide range of organic solvents can be obtained. By selecting an amine compound that dissolves in both organic solvents and water, it is also possible to obtain organic pigments that readily disperse in both organic solvents and water. Conversely, by selecting an amine compound that dissolves in one organic solvent A but not in another organic solvent B, it is possible to create pigments that readily disperse in organic solvent A but not in organic solvent B.For example, when dispersed and then formed into a coating film, it becomes possible to impart resistance to organic solvent B, preventing the organic pigment from leaching out.

[0026] The solubility of a compound in an organic solvent depends on the polarity relationship between the organic solvent and the compound. Specifically, compounds with similar polarities have good affinity for each other. As is generally known, the polarity of a compound is influenced by the polarity of its functional group, and in the case of polymers, it is influenced by the polarity of the main chain, side chains, and functional groups. Therefore, the desired polarity can be obtained by appropriately selecting these. Known chemical structures with high polarity include amines, as well as structures containing oxygen atoms such as ether groups, ester groups, hydroxyl groups, and carboxyl groups. Among ether groups, polyethylene oxide (polyethylene glycol) is particularly effective in increasing polarity. Typical chemical structures with low polarity include alkyl groups and benzene rings, which consist only of C and H. The amine compounds that can be used in this invention include, but are not limited to, those known as dispersants.

[0027] The structure of the amine compound is not limited, but so-called medium-sized molecules to high polymers with a molecular weight of approximately 500 or more are preferred. Examples of main chains include, but are not limited to, (1) polyethers, (2) polyacrylics (methacrylics), (3) polyurethanes, (4) polyalkyls, (5) polyesters, (6) polysiloxanes, and (7) other polyamines. The position of the amine is also not limited; the amine may constitute the main chain or the side chain, the nitrogen atom of the amine may constitute the chain or be bonded as a functional group. For example, the former includes those in which the imide ring constitutes part of the main chain or side chain (such as acrylic main-chain ring polymers), and the latter includes those having suspended amine functional groups. Furthermore, multiple types of chains may be combined in blocks, grafts, etc. Different functions can be imparted by combining multiple chains or functional groups, and some structures are controlled to control affinity to materials and media, such as polarity. For example, by controlling the position of the amine in the molecule, the affinity to organic pigment particles can be controlled, making them easier to adsorb. Furthermore, by introducing a structure with a different polarity from the main chain into the side chain and selecting an appropriate side chain, the polarity of the polymer can be adjusted, thereby controlling its solubility in various solvents. For example, by introducing a side chain with high polarity relative to the main chain, the overall polarity of the amine compound can be increased, or conversely, by introducing a side chain with low polarity, the overall polarity of the amine compound can be decreased, thus controlling the polarity of the compound through the combination of the main chain and side chains. For example, in cases where the main chain is acrylic (methacrylic) or urethane, there are examples where the polarity is increased by introducing a polyether with higher polarity than the main chain as a side chain. In addition, there are also examples where the affinity to particles and the affinity to organic solvents are controlled by various esters. Examples include those in which various esters, such as phosphate esters, carbonate esters, and acetate esters, are introduced, and it is known that phosphate esterification in particular improves the affinity to particles. The shape of the polymer is not particularly limited, and can be linear, comb-shaped, spherical, star-shaped, etc.

[0028] More specifically, the following can be mentioned as such polymer amine compounds: 1. Polyetheramines Polyetheramines are compounds having at least a polyether moiety and an amine moiety. The amine moiety may have the amine bonded to the end of the polyether main chain, or it may be bonded as a side chain. The polyether main chain may be linear or branched. Typical examples include polyetheramine compounds with a medium molecular weight of 500 to several thousand, having a structure in which the amine is bonded to the end of a linear polyether main chain.

[0029] The polyether portion typically includes (i) an addition polymer of ethylene oxide and / or (ii) propylene oxide, and in particular, an addition polymer of ethylene oxide (polyethylene glycol) can significantly increase polarity. For the amine portion, a primary amine is preferred because its high basicity leads to high reactivity with the acidic groups of the organic pigment. The amine portion may be at both ends of the main chain or at one end. Having the amine at only one end is preferable because the amine portion binds to the organic pigment, while the polyether portion is compatible with organic solvents.

[0030] Because these compounds are relatively low molecular weight, they dissolve rapidly in organic solvents. Surface-modified organic pigments obtained by reacting with such compounds also disperse rapidly in organic solvents with relatively small amounts of amine compound modification. Polyoxyalkyleneamines and polyoxyalkylene alkylamines, which are amine derivatives of polyalkylene oxides known as so-called Pluronic surfactants, also fall into this category. Representative examples of such compounds include those shown in the following molecular formulas.

[0031] [Chemical formula 1]

[0032] [Chemical Formula 1] In the case of R=CH3, x represents the amount of polyethylene oxide and y represents the amount of polypropylene oxide. Since polyethylene oxide is hydrophilic and polypropylene oxide is hydrophobic, the polarity can be adjusted by adjusting the ratio of x and y. For example, a polyetheramine with x / y = 19 / 3 (molecular weight 1000) disperses in organic solvents such as PMA and MEK, and because of the high proportion of ethylene glycol, it also dissolves in water.

[0033] In addition to the polyether and amine portions, there are also compounds that have alkyl portions such as aliphatic and aromatic functional groups. Examples of alkyl portions include phenol, t-butylphenol, cresol, and nonylphenol. Among these functional groups, those with structures having aliphatic and aromatic functional groups, such as t-butylphenol and nonylphenol, are particularly preferred in terms of the affinity of the resulting amine-modified organic pigment to organic solvents. Typical examples of compounds having such functional groups are polyoxyalkylene nonylphenyl ethers such as polyoxymethylene nonylphenyl ether, polyoxyethylene nonylphenyl ether, and polyoxypropylene nonylphenyl ether. In particular, there are compounds having a nonylphenol portion and a propylene glycol portion, as shown in the following chemical formula. The nonylphenol portion having an aromatic ring and a long-chain alkyl group has low polarity, and the propylene glycol portion also has relatively low polarity, so they are insoluble in water. However, as will be described later, they can be neutralized with acid and dissolved in water for use, and the resulting amine-modified organic pigment shows a strong affinity for organic solvents and disperses easily in organic solvents. A typical example of such a compound is shown in the following molecular formula. [Chemical formula 2]

[0034]

[0035] These commercially available products include Jeffamine-M600, M1000, M-2005, M-2070, M-3085, FL1000 (all brand names, manufactured by Huntsman), Solsperse 20000 (brand name, manufactured by Looprizole), and Genamin M41 / 2000 (brand name, manufactured by Clariant).

[0036] 2. These are polymers with a molecular weight ranging from several thousand to tens of thousands, possessing an amine in an acrylic amine polyacrylate main chain. The amine is introduced by using a monomer containing an amine as part of the monomer. There are block polymers and random polymers. Block polymers include vinyl polymer amines and acrylic polymer amines that undergo living radical polymerization, while random polymers include vinyl polymer amines and acrylic polymer amines that undergo free radical polymerization, but there are no particular restrictions on their use.

[0037] The polyacrylate main chain is produced by polymerizing one or more (meth)acrylic monomers. (Meth)acrylic monomers include (i) amine-containing (meth)acrylic monomers and (ii) amine-free (meth)acrylic monomers, but amines are introduced by using monomers that contain amines as at least some of the monomers. (i) Specific examples of amine-containing (meth)acrylic monomers include aminoethyl (meth)acrylate, aminopropyl (meth)acrylate, aminobutyl (meth)acrylate, etc.

[0038] Other examples include alkylammonium salts or arylammonium salts of acrylic acid or methacrylic acid.

[0039] Furthermore, the introduction of an amino group can also be done using amine-containing monomers other than amine-containing (meth)acrylic monomers. Typical examples of such monomers are amine compounds having a vinyl group or a ring-opening polymerizable nitrogen-containing functional group. Typical examples of ring-opening polymerizable nitrogen-containing functional groups include imine compounds, more specifically, ethyleneimine, propyleneimine, and trimethyleneimine. Typical examples of amine compounds having vinyl polymerization include alkyleneamines such as allylamine and vinylamine, amino group-containing styrenes such as aminostyrene, and various compounds having at least a vinyl group and a nitrogen heterocycle. Among such compounds having a vinyl group and a nitrogen heterocycle, those in which the nitrogen heterocycle portion has 5 or 6 members are more preferable, and the nitrogen heterocycle portion may be quaternized.

[0040] Specific examples of the compound having at least a vinyl group and a 5- or 6-membered nitrogen heterocycle include, for example, 2-vinylpyridine, 4-vinylpyridine, 1-vinylimidazole, 1-vinyl-1H-pyrazole, 1-vinyl-2-imidazoline, 2-vinyl-2-imidazoline, 2-vinylpyrazine, 2-vinyl-4,6-diamino-1,3,5-triazine, etc. In addition, as various addition-polymerizable oxazoline compounds, for example, 2-vinyl-2-oxazoline, 2-vinyl-4-methyl-2-oxazoline, 2-vinyl-5-methyl-2-oxazoline, 2-isopropenyl-2-oxazoline, 2-isopropenyl-4-methyl-2-oxazoline, 2-isopropenyl-5-methyl-2-oxazoline, 2-isopropenyl-5-ethyl-2-oxazoline, etc. Examples of the nitrogen-containing (meth)acrylic monomer capable of ring-opening polymerization include N-substituted maleimide having an amine-containing functional group as a substituent. Among these, 1-vinyl-1H-pyrazole, 1-vinyl-2-imidazoline, 2-vinyl-2-imidazoline, etc., and the above various addition-polymerizable oxazoline compounds are preferable. These addition-polymerizable oxazoline compounds polymerize by an addition-polymerizable functional group other than the oxazoline group, so that a polymer with a suspended oxazoline group is formed, and the portion can form a steric structure suitable for reacting with a hydrophilic organic pigment as an amine. In addition, N-substituted maleimide has the advantage that a nitrogen-containing heterocyclic structure can be introduced into the main chain by copolymerization with other ring-opening polymerizable monomers, and a desired amine can be introduced by a substituent.

[0041] The above various polymerizable amine compounds can be used alone or in combination of two or more. In particular, a compound having a vinyl group and a 5- or 6-membered nitrogen heterocycle can be used alone or in combination of two or more.

[0042] (ii) (meth)acrylic monomers that do not contain amines include low-polarity monomers and high-polarity monomers. Low-polarity monomers include those containing functional groups such as alkyl groups, aryl groups, and styrene. Examples include linear alkyl (meth)acrylates, cycloalkyl (meth)acrylates, aryl (meth)acrylates, and styrene compounds. These can be used individually or in combination of two or more.

[0043] Highly polar monomers include those containing glycol groups. More specifically, polyalkylene glycol (meth)acrylates are mentioned. Examples of polyalkylene glycols include polyethylene glycol, polypropylene glycol, and polybutylene glycol, which have 2 to 4 carbon atoms in their alkylene chains. These can be used individually or in combination of two or more. Examples of polyalkylene glycol (meth)acrylates include monofunctional or polyfunctional esters of polyalkylene glycol with 2 to 4 carbon atoms in its alkylene chain and acrylic acid or methacrylic acid. More specifically, examples include polyethylene glycol monomethacrylate, methoxypolyethylene glycol monomethacrylate, polyethylene glycol dimethacrylate, phenoxypolyethylene glycol acrylate, polypropylene glycol monomethacrylate, and polypropylene glycol diacrylate.

[0044] The method for polymerizing these various monomers to produce an acrylic polymer amine is not limited. It is also possible to form a main chain by polymerizing a (meth)acrylate monomer having an amine and a (meth)acrylate monomer not having an amine, or to form a main chain by polymerizing an amine other than (meth)acrylate and a (meth)acrylate monomer not having an amine. If an imine-based monomer is used as the amine, the amine can also be incorporated into the main chain. Amines may be further introduced as side chains into these main chains. Also, after forming a main chain by polymerizing only a (meth)acrylate monomer not having an amine, an amine may be introduced as a side chain. More specifically, examples include oxazoline group-containing polymers, which are copolymers of at least various styrene-based compounds and addition-polymerizable oxazoline compounds, and copolymers of a cyclopolymerizable monomer such as N-substituted maleimide having an amine-containing functional group as a substituent and other polymerizable monomers such as styrene-based monomers. Commercially available products of these include the Epocros (registered trademark) series (manufactured by Nippon Shokubai Co., Ltd.). Other commercially available products of polyacrylic-based compounds include DISPERBYK-2012 and DISPERBYK-2150 (both are trade names, manufactured by BYK Chemie), and Efka PX4320 and Efka PX4320 (both are trade names, manufactured by BASF).

[0045] 3. It is a polymer having a urethane-based amine main chain, having an amine, and having a molecular weight of about several thousand to several tens of thousands. By using a monomer containing an amine, an amine can be introduced into the polymer. It has a polyurethane main chain and usually has a plurality of amines, and the weight average molecular weight is mainly about several thousand to one hundred thousand.

[0046] Polyurethanes are generally obtained by addition polymerization of polyisocyanates and compounds having hydroxyl groups. In particular, by using a -NH2 group and / or -NHR group (R is an alkyl group having 1 to 4 carbon atoms) as the compound having hydroxyl groups, an amine can be introduced into the main chain. That is, in the present invention, the urethane polymer amine may not only have an amine in the main chain, but may also have an amine introduced as a side chain. The introduction of the amine can be achieved by selecting the monomer used when forming the polyurethane main chain. Specifically, the monomer may be (i) polyisocyanate and (ii) a compound having two or more functional groups that react with isocyanates, such as an -OH group, an -NH2 group and / or -NHR group (R is an alkyl group having 1 to 4 carbon atoms) or an -SH group, and further polymerization may be carried out by adding (iii) a compound having one functional group that reacts with isocyanates, such as an -OH group, an -NH2 group and / or -NHR group (R is an alkyl group having 1 to 4 carbon atoms) or an -SH group.

[0047] (i), (ii), and (iii) may each be a combination of multiple compounds. The structure of the resulting polyurethane can be adjusted by the proportions of (i), (ii), and (iii), especially the proportion of (ii) and (iii). Furthermore, by using compounds having at least an -NH2 group and / or an -NHR group as (ii) and / or (iii), and adjusting the ratio so that the amount of amine is in excess of the amount of isocyanate, polyurethane containing amines can be synthesized. For the compounds of (ii) and (iii) that have functional groups that react with isocyanates, the dispersibility in various organic solvents and solubility in water can be controlled by adjusting the composition ratio of low-polarity monomers and high-polarity monomers.

[0048] (i) As the polyisocyanate, a polyisocyanate having an average of 2.5 to 6 isocyanate functional groups is preferred. Polyisocyanates include aromatic isocyanates and aliphatic isocyanates. Representative aromatic isocyanates include products such as "Desmodulo L" (registered trademark, manufactured by Sumika Bayer Urethane Co., Ltd.), "Desmodulo N" (registered trademark, manufactured by Sumika Bayer Urethane Co., Ltd.), "Desmodulo HL" (registered trademark, manufactured by Sumika Bayer Urethane Co., Ltd.), and "Desmodulo IL" (registered trademark, manufactured by Sumika Bayer Urethane Co., Ltd.), as well as "Porren KC" and "Porren HR" (both trade names, manufactured by Essea Piichi Co., Ltd.). Aliphatic diisocyanates include tolylene diisocyanate (TDI), isophorone diisocyanate (IPDI), and trimelic isophorone diisocyanate.

[0049] Compounds of (ii) or (iii) having a functional group that reacts with an isocyanate, such as an -OH group, an -NH2 group and / or an -NHR group (where R is an alkyl group having 1 to 4 carbon atoms) or an -SH group, include diols, triols, diamines, dialkanolamines and monoalkanolamines having 2 to 12 carbon atoms; dihydroxydialkyl sulfides and dihydroxysulfones, for example, butanediol, hexanediol, cyclohexanedimethanol, neopentyl glycol, ethylene glycol, alkyl-substituted dialkanolamines, glycerol, trimethylolpropane, fatty acid dialkanolamides, thiodiglycols and di-(4-hydroxyphenyl)-sulfones. Highly polar compounds include polyoxyalkylene glycols with a molecular weight of 600 to 3000, more preferably 1000 to 3000, and most preferably 600 to 1500. Polycaprolactone polyols obtained by polymerization of lactones using compounds having two or three hydroxyl groups as starting components may also be used. Polycaprolactone polyols are expected to have improved compatibility and solubility with resins due to the inclusion of lactone chains.

[0050] The amine may be a nitrogen-containing heterocyclic group. Among the heterocyclic groups, triazole, pyrimidine, imidazole, pyridine, morpholine, pyrrolidine, piperazine, benzimidazole, benzothiazol, and / or triazine groups are preferred. Of these heterocyclic groups, pyrrolidine, piperazine, and benzimidazole groups are particularly preferred. Block polymers with other types of main chains are especially preferred. Specifically, examples include block polymers of urethane and acrylic chains, as described in JP 2011-516644, and more specifically, hydrophobically modified polyurethanes and / or modified ureas, such as urea-urethane polymers. Furthermore, ester derivatives such as phosphate esters, as described in JP 2014-524944, are preferred.

[0051] Commercially available products include DISPERBYK167 and DISPERBYK164 (both brand names, manufactured by Bic Chemie).

[0052] 4. Polyamines Generally, polyamines refer to compounds that have multiple amines in their molecule, but here, regardless of whether they fall under the various polymers mentioned above, the term mainly refers to those that contain N as the main chain, but is not limited to that. Typical examples include compounds that contain the constituent parts represented by the following chemical formulas.

[0053]

[0054] Such compounds are obtained by polymerizing polymerizable amine compounds, typically amine compounds having a vinyl group or a ring-opening polymerizable nitrogen-containing functional group. Typical examples of ring-opening polymerizable nitrogen-containing functional groups include imine compounds and oxazoline compounds, and more specifically, various alkylimines and various 2-substituted or 3-substituted oxazolines or oxazolidines. 1 If the polarity of the part is too high, it will be easily soluble in water and have low affinity for organic solvents. Therefore, R １ Suitable alkyl groups include those having 4 or more carbon atoms, for example, alkyl groups having 4 to 6 carbon atoms, and more preferably alkyl groups having 4 or 5 carbon atoms. ２A hydrogen or amine-containing functional group is preferred.

[0055] Furthermore, various esters of such polyamine chains can be mentioned. It is presumed that the polyamine portion reacts with and binds to the hydrophilic group of the organic pigment, and the ester portion improves affinity with organic solvents, leading to dispersion stabilization due to steric hindrance. The ester portion is not limited, but preferred specific examples include salts of at least one of an acidic phosphate chain ester and an acidic phosphite chain ester with a polyamine. Here, "salt of an acidic (or )phosphite chain ester and a polyamine" means a polyamine salt of an acidic (or )phosphite chain ester, where some or all of the P-OH groups of the acidic (or )phosphite chain ester are deprotonated. － This refers to a salt containing an anion having a group and a cation having an ammonium group in which some or all of the amino groups of the base polyamine are protonated. For example, one such compound is described as a dispersant (C) in Japanese Patent Application Publication No. 2022-7782. A commercially available product known as such a compound is Dysperbyk-145 (trade name, manufactured by Bic Chemie).

[0056] As mentioned above, in order for the resulting amine-modified organic pigment to self-disperse in an organic solvent, it is preferable that the amine compound dissolves in the target solvent used. As shown in the examples described later, the inventors' studies have shown that if the amine compound dissolves in the solvent, the organic pigment modified with it will self-disperse in that solvent. The target solvent is not limited and can be selected according to the intended use.

[0057] Specifically, solvents used in a wide range of applications where organic pigments are used, such as paints, inks, and color filters, include, but are not limited to, acetate solvents (e.g., PMA (propylene glycol monomethyl ether acetate), butyl acetate), ketone solvents (e.g., MEK (methyl ethyl ketone), MIBK (methyl isobutyl ketone), cyclohexanone), alcohol solvents (e.g., IPA (isopropyl alcohol), methoxypropanol), ether solvents (e.g., 1,3-dioxolane), ester solvents (e.g., butyl acetate, ethyl acetate), glycol solvents (e.g., diethyldiglycol), and amine solvents (e.g., NMP (N-methyl-2-pyrrolidone), DMF (N,N-dimethylformamide)). Of these, for acetate solvents and ketone solvents, polyetheramines, acrylic amines, urethane amines, and phosphate ester salts of polyamines, as mentioned above, exhibit excellent compatibility. For alcohol solvents (e.g., IPA, methoxypropanol), polyetheramines are particularly suitable.

[0058] Furthermore, for example, when an organic pigment is dispersed in PMA and combined with a resist resin for color filters for use in a color filter, acrylic amines, urethane amines, and polyetheramines are preferred as polymer amine compounds that can dissolve or disperse in PMA. Also, when an organic pigment is dispersed in an acrylate monomer and combined with an acrylic resin, alkyd resin, etc., for use in a UV-curing paint, acrylic amines are preferred as amine compounds that can dissolve or disperse in the acrylate monomer. In addition, for paints, the solvent is selected according to the binder and method of use, such as acrylic resin, alkyd resin, melamine resin, polyester resin, isocyanate resin, and epoxy resin, and an amine compound that can dissolve or disperse in each solvent can be appropriately selected.

[0059] As explained above, the amine compound should be selected considering its solubility in the target solvent to which the organic pigment will be mixed. In other words, an amine compound that dissolves in the target solvent should be selected and reacted with the hydrophilic organic pigment. It is also possible to select an amine compound that dissolves in multiple solvents.

[0060] Furthermore, the organic pigments modified with the amine compounds of the present invention are suitable not only for use in organic solvents but also for blending with polymerizable monomers in paints, resin compositions, and the like. A colored polymer is obtained by dispersing the organic pigment in a polymerizable monomer and polymerizing the monomer. Various forms exist, including bulk molding and application in ink form followed by UV curing. Compositions containing such monomers that do not contain organic solvents or contain only a very small amount (so-called organic solvent-free) have been widely developed and proposed in recent years due to their environmental impact from organic solvents. Such organic solvent-free monomer compositions have been proposed for use in display forming compositions, ink compositions for inkjet printers, and the like. However, the present invention is preferable because it allows for the selection of amine compounds considering compatibility with the target monomer, thus expanding the range of applications for organic solvent-free use. Examples of such polymerizable monomers include acrylic monomers (BZA (benzyl acrylate), PEA (phenoxyethyl acrylate), 1,6-hexanediol acrylate, etc.). Acrylic amines and polyetheramines exhibit excellent compatibility with these monomers. In addition to those listed above, other commercially available amine compounds include, for example, BYKLPN-21324 and BYKLPN-22329 (both trade names, manufactured by Bic Chemie).

[0061] [Mixing Ratio] The mixing ratio of the organic pigment to the amine compound is preferably 1 to 500 parts by weight of the amine compound in terms of solid content per 100 parts by weight of the organic pigment. More preferably, it is 10 to 400 parts by weight, and most preferably, 50 to 200 parts by weight. If the amount of amine compound is too small, the surface modification of the organic pigment may not be sufficient, and the dispersibility of the organic pigment in the target solvent may not be sufficient. If the amount of amine compound is too large, the performance of the organic pigment, such as hue, may not be fully realized. Furthermore, the amount of amine compound should be equal to or greater than the amount of hydrophilic functional groups on the surface of the organic pigment. When using an organic pigment that does not have hydrophilic functional groups, the amount of amine compound required can be calculated from the amount of hydrophilizing agent used in the hydrophilization process, the molecular weight of the amine compound, and the amine value. When using an organic pigment that originally has hydrophilic functional groups, the amount of amine compound required can be calculated by means of titration or other methods.

[0062] [Reaction between Organic Pigment and Amine Compound] When the hydrophilic organic pigment described above is mixed with an amine compound in an aqueous medium, the hydrophilic functional groups on the surface of the organic pigment react with the amine compound and bond. That is, the carboxyl groups and / or sulfone groups that were originally present on the surface of the organic pigment or introduced by oxidation treatment, sulfonation treatment, etc., react with the amine to form one or more bonds of -SO2NH-, -SO2N-, -CONH-, and -CON-. Therefore, the organic pigment and the amine compound are bonded via these bonds. Furthermore, from the viewpoint of dispersibility in organic solvents, it is preferable to react with an amount of amine compound greater than the amount of sulfone groups and / or carboxyl groups on the surface of the organic pigment. This is because the dispersibility in organic solvents is higher when the sulfone groups and / or carboxyl groups react with the amine compound and the amine compound is present on the pigment surface, rather than when unreacted sulfone groups and / or carboxyl groups remain on the pigment surface. The bond between the organic pigment and the amine compound formed by this reaction is considered to be strong. Furthermore, it is presumed that removing water from the mixture of organic pigment and amine promotes dehydration and further advances the reaction. Also, as shown in the examples and comparative examples described later, primary amines, secondary amines, and cyclic amines disperse in organic solvents, while tertiary amines and quaternary ammonium salts (excluding cyclic amines) do not disperse in organic solvents. This is thought to indicate that primary and secondary amines undergo a substitution reaction between hydrogen atoms and hydrophilic functional groups, and cyclic amines undergo ring cleavage and react with hydrophilic functional groups, but tertiary amines and quaternary ammonium salts (excluding cyclic amines) do not react because they do not have hydrogen atoms or reaction sites. In the present invention, the aforementioned hydrophilic organic pigments are used as organic pigments, and they have a sufficient amount of reactive functional groups on their surface, more specifically, a sufficient amount of hydrophilic functional groups on their surface. Therefore, they are uniformly dispersed in an aqueous medium, and these functional groups react with and bond with the amine compound, resulting in self-dispersibility in organic solvents.

[0063] [Dissolution and Dispersion of Amine Compounds] The reaction between hydrophilic organic pigments and amine compounds can be carried out by mixing them in an aqueous medium. The mixing method is not limited, but the amine compound may be dissolved or dispersed in the aqueous medium beforehand before being mixed with the organic pigment dispersion. The aqueous medium here can be mainly water-based, and water alone is acceptable, or a water-soluble solvent may be added. Typically, a medium containing 50% by weight or more water is preferred. If the amine compound is water-soluble or dispersible in an aqueous medium, it may be used as is. Otherwise, it is preferable to dissolve or disperse it in the aqueous medium beforehand by neutralization or a mechanical process.

[0064] Amine compounds can be broadly classified into (a) amine compounds that are insoluble in water and (b) amine compounds that are soluble in water, from the viewpoint of their solubility in water. In the case of (a), the amine can be made soluble in water by neutralizing it with an acid before use. The acid that can be used is not particularly limited, but in order to disperse in an organic solvent, it is preferable to use one with as little residual acid component as possible. This is because excess acid component can inhibit dispersion in the organic solvent and cause insoluble matter. For this reason, an acid with a low boiling point and which can be removed in excess during the drying process, such as acetic acid, is preferred. Acids that are easily soluble in organic solvents, such as benzyl chloride and phosphoric acid, are also suitable. In this case, a commercially available neutralization salt may be used, or the amine compound may be neutralized and used by oneself. The amount of acid used for neutralization can be an equivalent amount, or it can be more or less, but too little is undesirable as it will not dissolve in water, while too much will result in residual acid that will not disperse in the organic solvent, as mentioned above, so it is sufficient to neutralize with an amount that allows the amine compound to dissolve in water.

[0065] Examples of type (a) include JEFFAMINE FL-1000 (trade name, manufactured by Huntsman), DIPERBYK-167 (trade name, manufactured by BIC Chemie), and examples of type (b) include polyetheramines (JEFFAMINE M-600, M-1000, M-2005, M-2070, M-3085 (trade names, manufactured by Huntsman), Genamin M41 / 2000 (trade name, manufactured by Clariant Specialty Chemicals), Solsperse 20000 (trade name, manufactured by Looprizole)), BYKLPN-21324, BYKLPN-22329, DISPERBYK-2012, DISPERBYK-2150, DISPERBYK-145 (trade names, manufactured by BIC Chemie).

[0066] [Aqueous Medium] Any aqueous medium can be used as the medium for reacting the organic pigment with the amine compound. Here, an aqueous medium is any liquid that is mainly water, and water alone is acceptable, or an organic solvent may be added. It is preferable that the water content (by weight) of the total liquid be 30% or more, preferably 50% or more, and more preferably 70% or more. Depending on the type of amine compound, some products contain a small amount of organic solvent to dissolve the amine compound, and in some cases, the presence of a solvent to ensure uniform mixing with the aqueous medium is preferable, but it is necessary that there is at least enough water to ensure that the hydrophilic organic pigment is uniformly dispersed.

[0067] The concentration of organic pigments and amine compounds in an aqueous medium is important because if there is too little water, the components will not mix uniformly, and the reaction will not be uniform. Therefore, the concentrations of organic pigments and amine compounds are not particularly limited as long as they can be mixed uniformly and dispersed using the selected dispersion device, such as a stirrer or bead mill, and the viscosity of the dispersion changes depending on the particle size and surface oxidation state of the organic pigment, and the viscosity of the aqueous solution of the amine compound changes depending on the molecular weight, etc., so the appropriate concentration will also change accordingly. However, it is sufficient to adjust it appropriately considering the reaction efficiency and workability, and usually the content of organic pigment in the total mixture is 30 wt% or less, preferably 20 wt% or less, 0.5 wt% or more, preferably 5 wt% or more, and usually around 10 wt% is most preferable.

[0068] [Method of reaction] The reaction between the organic pigment and the amine compound can be carried out by mixing them in an aqueous medium. The specific method of mixing the organic pigment and the amine compound is not limited, but for example, the following methods can be appropriately selected: 1. Disperse the organic pigment in an aqueous medium to make a dispersion, and add the amine compound solution dropwise while stirring. 2. Add the dispersion of the organic pigment in an aqueous medium dropwise to the solution or dispersion of the amine compound dropwise while stirring. 3. While stirring the aqueous medium, simultaneously add the dispersion obtained by dispersing the organic pigment in an aqueous medium and the dispersion or solution of the amine compound dropwise and allow them to react. 4. Add the organic pigment and the amine compound simultaneously to an aqueous medium and mix, disperse, and allow them to react.

[0069] The reaction occurs when a water-dispersible organic pigment and an amine compound are mixed in an aqueous medium, but stirring is preferred. Alternatively, dispersion or stirring may be performed using a disperser such as a bead mill, ultrasonic disperser, or jet mill. The reaction proceeds sufficiently at room temperature, but it is also possible to accelerate the reaction by heating the aqueous medium to a temperature that does not boil.

[0070] [Separation from Aqueous Medium] After the reaction of an organic pigment with an amine compound, the amine-modified organic pigment can be obtained by removing the aqueous medium. There are types in which the product separates from the aqueous medium after the reaction and types in which it does not, and a suitable method for removing the aqueous medium can be adopted for each. If the amine compound does not have hydrophilic groups or groups that can become hydrophilic other than the amino group, the separation of the product from water can be visually confirmed. (Example 1 described later) This type can be easily separated from the aqueous medium by filtration. A dried product can also be obtained by further drying. On the other hand, if the amine compound has hydrophilic groups or groups that can become hydrophilic other than the amino group, the product is difficult to separate from water. In this type, a dried product can be obtained by drying by spray drying or the like. Even in the type that does not separate from the aqueous medium, depending on the water solubility characteristics of the amine compound, it is possible to separate it from water by adjusting the solubility conditions such as concentration and pH. For amine compounds whose solubility in water changes with concentration, reducing the water content by heating after the reaction will result in a high concentration and separation from water. It is also possible to obtain a high-concentration dispersion by solvent substitution.

[0071] Organic pigments may originally contain inorganic substances such as inorganic salts, and in addition, inorganic substances may be introduced and remain in the organic pigment during reactions that impart hydrophilic functional groups such as sulfone groups and carboxyl groups. Since such inorganic substances are insoluble in organic solvents and can inhibit self-dispersion in organic solvents, it is preferable to remove them as much as possible. However, if separation from the aqueous medium is required, they can be easily removed by washing with water during filtration. If separation from the aqueous medium is not required, ultrafiltration may be performed.

[0072] [Confirmation of the reaction] If the amine compound does not have hydrophilic groups or groups that can become hydrophilic other than the amino group, the product will separate from water, indicating that a reaction has occurred. This is presumed to be because, while the water-dispersible organic pigment and the amine compound were dissolved or dispersed in water before the reaction, the hydrophilic functional groups on the surface of the hydrophilic organic pigment reacted and bonded with the amino group of the amine compound, causing the dispersibility in water provided by the hydrophilic functional groups that contributed to the dispersion of the hydrophilic organic pigment in water to be lost. On the other hand, if the amine compound has hydrophilic groups or groups that can become hydrophilic other than the amino group, although the dispersibility in water provided by the hydrophilic functional groups on the surface of the hydrophilic organic pigment is lost, the amine compound bonded to it has hydrophilic groups other than the amino group, so it disperses in water due to these hydrophilic groups and does not separate from water. Even in this case, as will be described later, when the organic pigment separated from the aqueous medium is added to an organic solvent, it disperses rapidly, confirming that the amine compound reacted and bonded in both cases.

[0073] As described above, the amine-modified organic pigment of the present invention can be obtained. As can be seen from the above description, the amine-modified organic pigment of the present invention can exist in a dispersed state in water, as well as in a cake-like state separated from water. Furthermore, it can exist in particulate form after drying. As for drying methods, it may be dried in a dryer and then pulverized in a pulverizer, or it may be dried by spray drying. In any case, the amine compound is bound to the surface of the organic pigment, and since this amine compound is soluble in the desired organic solvent, when this organic pigment is added to an organic solvent, it can be dispersed very easily and uniformly without the addition of dispersants or the like.

[0074] It is hypothesized that the amine or ionized ammonium ions of the amine compound approach and adsorb to hydrophilic functional groups such as sulfone groups and carboxyl groups on the surface of the organic pigment through electrostatic interactions, and that further bonding can be formed by the removal of water. The formation of a somewhat continuous bonding state can be confirmed by the fact that the amine-modified organic pigment, after the water has been removed as described above, disperses easily when added to an organic solvent.

[0075] If no bonding occurs, the amine compound would likely be removed along with the water during the water removal process. Therefore, the organic pigment, after water removal, would not disperse but would instead aggregate when added to an organic solvent. In contrast, according to the present invention, when a water-dispersible organic pigment is used and mixed with an amine compound that has affinity for a desired organic solvent in an aqueous medium, the amine-modified organic pigment, after the aqueous medium is removed, readily disperses in the organic solvent without the need for dispersants. This confirms that the amine compound, which has affinity for the organic solvent, is bonded to the surface of the organic pigment.

[0076] As described above, the present invention allows for the production of surface-modified organic pigments that disperse easily in various organic solvents by selecting the appropriate amine compound. In the case of type (a) mentioned above, the site that binds to the surface is hydrophobic, resulting in good separation from water, easy dispersion in organic solvents without the need for a dispersant, and no dispersion in aqueous media (Figure 5). Therefore, it is possible to obtain surface-modified organic pigments with high water resistance.

[0077] In the case of amine compounds whose solubility in water changes with concentration, they tend to have relatively low solubility in water, making them less prone to self-dispersion in water and thus more water-resistant. On the other hand, by selecting an amine compound that has affinity for both aqueous and organic solvents, it is possible to obtain organic pigments that self-disperse in both organic and aqueous media.

[0078] Conventional organic pigment powders aggregate when simply mixed with organic solvents, requiring pre-dispersion in the organic solvent using a dispersion device and dispersant. However, the amine-modified organic pigment of the present invention self-disperses in organic solvents, allowing for use simply by mixing it with the organic solvent. While water-based self-dispersing organic pigments that disperse simply by mixing with water have existed, this is the first self-dispersing organic pigment for organic solvents. The amine-modified organic pigment of the present invention, which self-disperses in organic solvents, can be sold in powder and paste forms that do not contain organic solvents. Compared to conventional organic pigment dispersion liquid products containing organic solvents, this offers several advantages, including (1) reduced transportation and storage costs due to the inclusion of organic solvents, and (2) elimination of the need for regulatory management of organic solvents.

[0079] The present invention will be described in more detail below with reference to examples. Note that "parts" refers to "parts by weight" and "%" refers to "weight percent". (Synthesis Example 1: Production of 3% sulfonated phthalocyanine pigment) 1. 1. Hydrophilic group introduction: 0.1 g of sodium nitrite was dissolved in 89.6 g of ion exchanger in a 200 ml polypropylene beaker ("Desk Cup" (manufactured by Teraoka Co., Ltd.) by stirring to prepare an aqueous sodium nitrite solution. 10 g of pigment blue 15:0 ("HEUCO Blue 501501" (trade name, manufactured by Heubach Color)) and 0.3 g of sulfanilic acid were added to a 500 ml Desk Cup. The entire 89.7 g of the aforementioned aqueous sodium nitrite solution was then added, followed by the addition of 230 g of Sepul ER120S (manufactured by Saint-Gobain). After stirring with a dissolver for 2 hours, the mixture was filtered through a 110 mesh nylon mesh to obtain a 3% sulfonated phthalocyanine pigment dispersion (hereinafter referred to as "dispersion 1"). 2. Particle size measurement: Dispersion 1 was measured using a particle size distribution analyzer (NanoTrack WAVE, manufactured by MicroTrack Bell Co., Ltd.). II) The particle size D50 was measured after diluting the solution with water to achieve the required reflected light intensity range for the measuring device, and the presence or absence of aggregates in the dispersion was visually observed. The results are shown in Table 2.

[0080] 3. Evaluation of dispersibility in ammonia water (confirmation of hydrophilicity of pigment) Dispersion 1 was dried in a dryer at 110°C until the water was removed and the weight was constant, and the 3% sulfonated phthalocyanine pigment (hereinafter referred to as "hydrophilic pigment 1") was recovered. 1 part by weight of hydrophilic pigment 1, 1 part by weight of 25% ammonia water, and 8 parts by weight of ion-exchanged water were placed in a 100 ml S-bottle (manufactured by Kokugo Co., Ltd.), 23 g of Sepul ER120S was added, and the mixture was dispersed in a paint shaker (manufactured by Asada Iron Works Co., Ltd.) for 30 minutes to obtain evaluation solution 1.

[0081] Evaluation solution 1 was diluted with water to the required reflected light intensity range using a particle size distribution analyzer (NanoTrack WAVE II, manufactured by MicroTrack Bell Co., Ltd.), and the particle size D50 was measured. The results are shown in Table 3. Evaluation solution 1 was dropped onto a glass plate placed on white copy paper using a 2 ml poly dropper (manufactured by AS ONE Corporation), and then ion-exchanged water was dropped using another 2 ml poly dropper. The appearance of the dropped material was observed, and photographs were taken. The results of the appearance observation are shown in Table 3, and the photographs are shown in Figure 1.

[0082] (Synthesis Example 2: Production of 10% sulfonated phthalocyanine pigment) Except for the amounts of sulfanilic acid, sodium nitrite, and deionized water added during the preparation of the sodium nitrite aqueous solution, which are shown in Table 1, a 10% sulfonated phthalocyanine pigment dispersion 2 (hereinafter referred to as "dispersion 2") was produced in the same manner as in Synthesis Example 1, and 2. particle size measurement and 3. evaluation of dispersibility in ammonia water were performed in the same manner as in Synthesis Example 1. Figure 2 shows the photograph taken during the evaluation of dispersibility in ammonia water. 3. The pigment recovered during the evaluation of dispersibility in ammonia water (confirmation of the hydrophilicity of the pigment) is referred to as "hydrophilized pigment 2", and the evaluation solution is referred to as "evaluation solution 2".

[0083] (Synthesis Example 3: Production of 3% sulfonated quinacridone pigment) A 3% sulfonated quinacridone pigment dispersion (hereinafter referred to as "dispersion 3") was produced using the same procedure as in Synthesis Example 1, except that pigment red 122 ("TONER MAGENTA E" trade name, manufactured by Clariant) was used instead of pigment blue 15:0 as the pigment. 2. Particle size measurement and 3. Evaluation of dispersibility in ammonia water were performed using the same method as in Synthesis Example 1. Figure 2 shows a photograph taken during the evaluation of dispersibility in ammonia water. 3. The pigment recovered during the evaluation of dispersibility in ammonia water (confirmation of pigment hydrophilicity) is referred to as "hydrophilized pigment 3," and the evaluation solution is referred to as "evaluation solution 3."

[0084] (Synthesis Example 4: Production of 10% sulfonated quinacridone pigment) A 10% quinacridone pigment dispersion (hereinafter referred to as "dispersion 4") was produced in the same manner as in Synthesis Example 3, except that the amounts of sodium nitrite and deionized water added during the preparation of sulfanilic acid and sodium nitrite aqueous solution were as shown in Table 1. 2. Particle size measurement and 3. Evaluation of dispersibility in water were performed in the same manner as in Synthesis Example 1. Figure 4 shows a photograph taken during the evaluation of dispersibility in ammonia water. 3. The pigment recovered during the evaluation of dispersibility in ammonia water (confirmation of pigment hydrophilicity) is referred to as "hydrophilized pigment 3," and the evaluation solution is referred to as "evaluation solution 3." The amounts added in Table 1 are shown in grams.

[0085] (Synthesis Example 5: Production of 10% Carboxylated Phthalocyanine Pigment) 0.5 g of sodium nitrite was dissolved in 88.5 g of ion exchanger in a 200 ml polypropylene beaker ("Desk Cup" (manufactured by Teraoka Co., Ltd.) by stirring to prepare an aqueous sodium nitrite solution. 10 g of Pigment Blue 15:3 ("PHTHALO BLUE BS-02W" (trade name, manufactured by Wellton Chemical)) and 1 g of 4-aminobenzoic acid were added to a 500 ml Desk Cup as blue pigments. The entire 89 g of the aforementioned aqueous sodium nitrite solution was then added, followed by the addition of 230 g of Sepul ER120S (trade name, manufactured by Saint-Gobain). After stirring at room temperature for 2 hours in a dissolver, the mixture was filtered through a 110 mesh nylon mesh to recover a 10% carboxylated phthalocyanine pigment dispersion (hereinafter referred to as "Dispersion 5"). 2. Particle size measurement and 3. Evaluation of dispersibility in water were performed using the same method as in Synthesis Example 1. 3. Figure 4 shows photographs taken during the evaluation of dispersibility in ammonia water. 3. The pigment recovered in the evaluation of dispersibility in ammonia water (confirmation of the hydrophilicity of the pigment) is referred to as "Hydrophilic Pigment 5," and the evaluation solution is referred to as "Evaluation Solution 5."

[0086] The dispersibility of "HEUCO Blue 501501," "TONER MAGENTA E," and "Blue BS-02W" before sulfonation or carboxylation in the synthesis examples was evaluated in the same manner as in Synthesis Example 1. 3. Dispersibility in aqueous ammonia was performed. The evaluation solutions were designated "Evaluation Solution A," "Evaluation Solution B," and "Evaluation Solution C," respectively. Table 3 shows the results of visual observation of the evaluation solutions, and Figures 6-8 show the photographs taken.

[0087]

[0088]

[0089]

[0090] 5. Confirmation of hydrophilicity: As shown in Table 2, all hydrophilic pigments obtained in Synthesis Examples 1 to 5 exist in a dispersed state with a sharp particle size distribution without aggregation in water.

[0091] The results shown in Table 3 indicate that the hydrophilic pigments obtained in Synthesis Examples 1 to 5 all exist in a dispersed state with a sharp particle size distribution without aggregation in ammonia water. Furthermore, a comparison of Figures 1 to 5 and Figures 6 to 8 shows that while the non-hydrophilic pigments aggregate in ammonia water, the hydrophilic pigments from Synthesis Examples 1 to 5 do not aggregate in ammonia water, indicating that hydrophilicity has been imparted and that they qualify as hydrophilic organic pigments.

[0092] (Examples) 1. Using dispersions 1 to 5 obtained in Amine Modification Synthesis Examples 1 to 5 and the compounds shown in Table 4 as amine compounds, organic pigments were amine-modified using the following methods in the combinations shown in Table 5. Note that compound 1 is a substance that does not contain amine.

[0093]

[0094]

[0095] (Example 1) 19.2 parts of amine compound 1 (10 parts solid) were mixed with 38.4 parts of 90% acetic acid and stirred with a stirrer until the liquid became clear to dissolve amine compound 1. Next, 50 parts of dispersion 1 (5 parts pigment) were mixed with the above amine compound solution and stirred with a stirrer at room temperature until the pigment separated and the supernatant became pale in color. After that, the mixture was filtered with 5A filter paper (manufactured by Advantec Toyo Co., Ltd.), washed with deionized water, and the filtrate was collected. The obtained filtrate was dried in a dryer at 110°C until the moisture was removed and the weight was constant, thereby obtaining an amine-modified organic pigment as a solid. (Example 2) 10.5 parts of amine compound 4 (10 parts solid) and 50 parts of dispersion 2 (5 parts pigment) were mixed and stirred with a stirrer at room temperature until the liquid color appeared uniform. After the above processing, the material was dried in a dryer at 110°C until moisture was removed and the weight became constant, thereby obtaining the amine-modified organic pigment as a solid.

[0096] (Examples 5, 11, 15, 16) The same procedure as in Example 1 was followed, except that the components and their amounts were as shown in Table 5, and amine-modified organic pigments were obtained as solids. (Examples 3, 4, 6-10, 12-14, 17-19) The same procedure as in Example 2 was followed, except that the components and their amounts were as shown in Table 5, and amine-modified organic pigments were obtained as solids. (Comparative Examples 1, 2, 5-16) The same procedure as in Example 2 was followed, except that the components and their amounts were as shown in Table 5, and solids were obtained. (Comparative Example 3) Evaluation liquid A was dried in a dryer at 110°C until the moisture was removed and the weight became constant, and the powder was recovered. (Comparative Example 4) Evaluation liquid B was dried in a dryer at 110°C until the moisture was removed and the weight became constant, and the powder was recovered.

[0097] (Comparative Example 17) The dispersion 2 prepared in Synthesis Example 2 was dried at 110°C until the weight was constant to remove water and recover a 10% sulfonated phthalocyanine pigment (hereinafter referred to as "hydrophilic pigment 2"). To the hydrophilic pigment 2, an amount of organic solvent (PMA) was added such that the ratio of hydrophilic pigment:PMA = 5.7:44.3 (by weight) was calculated based on the amount of pigment blue used in Synthesis Example 2 (15:0). Then, a solution of amine compound 1 was added in an amount such that the ratio of hydrophilic pigment:amine compound = 5.7:19.2 based on the solid content of the amine compound, and the mixture was mixed with a magnetic stirrer for 5 minutes. The resulting mixture was dried in a dryer at 110°C until the water was removed and the weight was constant to obtain a solid. (Comparative Example 18) To the hydrophilic pigment 2 recovered in the same manner as in Comparative Example 17, an amount of organic solvent (PMA) was added such that the ratio of hydrophilic pigment:PMA = 5.7:44.3 (by weight) was calculated based on the amount of pigment blue used in Synthesis Example 2 (15:0). Then, a solution of amine compound 4 was added in an amount such that the ratio of hydrophilic pigment:amine compound = 5.7:10.5 based on the solid content of the amine compound, and the mixture was mixed with a magnetic stirrer for 5 minutes. The resulting mixture was dried in a dryer at 110°C until the water was removed and the weight was constant to obtain a solid. (Comparative Example 19) To the hydrophilic pigment 2 recovered in the same manner as in Comparative Example 17, a solution of amine compound 1 was added in an amount such that the ratio of hydrophilic pigment:amine compound = 5.7:19.2 based on the solid content of the amine compound, and the mixture was mixed with a magnetic stirrer for 5 minutes. The resulting mixture was dried in a dryer at 110°C until the water was removed and the weight was constant to obtain a solid. (Comparative Example 20) To the hydrophilic pigment 2 recovered in the same manner as in Comparative Example 17, a solution of amine compound 4 was added in an amount such that the ratio of hydrophilic pigment to amine compound was 5.7:10.5 in terms of the solid content of the amine compound, and the mixture was mixed with a magnetic stirrer for 5 minutes. The resulting mixture was dried in a dryer at 110°C until the water was removed and the weight was constant to obtain a solid. (Comparative Examples 21, 22) Except that the dispersion 4 prepared in Synthesis Example 4 was used instead of the dispersion 2 prepared in Synthesis Example 2, and the amount of amine compound 2 shown in Table 6 was added instead of the solution of amine compound 4, an amount of organic solvent (PMA) shown in Comparative Example Table 6 was added, and an amine modification was attempted by adding a solution of amine compound 2 in the same manner as in Example 5.The resulting mixture was dried in a dryer at 110°C until the water was removed and the weight was constant to obtain a solid. (Comparative Examples 23, 24) Instead of dispersion 2 prepared in Synthesis Example 2, dispersion 4 prepared in Synthesis Example 4 was used, and the hydrophilic pigment 4 was recovered by drying in the same manner as in Comparative Example 17 to remove water. Amine compound 2 was added in the amount shown in Table 6 and mixed with a magnetic stirrer for 5 minutes. The resulting mixture was dried in a dryer at 110°C until the water was removed and the weight was constant to obtain a solid. Table 6 shows the types and amounts of pigments used in Comparative Examples 17 to 24, the types and amounts of amine compounds, and the types and amounts of solvents added when attempting amine modification. In Tables 6 and 7, the "Type of Solvent" and "Amount (parts)" in the "Amine Compound" column indicate the solvent contained in the amine compound and its amount. Amine compound 1 and amine compound 4 are products containing PMA, while amine compound 2 is a product that does not contain a solvent.

[0098]

[0099] (Examples 20-29, Comparative Examples 25-27) Except for adding an organic solvent (PMA or ethanol) in the amounts shown in Table 7 to dispersion 2 and amine compound solution, the same procedure as in Example 5 was performed to attempt amine modification of the pigment, and the product was dried in the same manner as in Comparative Example 17 to obtain a solid. The types and amounts of pigments, amine compounds, and solvents added when attempting amine modification in Examples 20-29 and Comparative Examples 25-27 are shown in Table 7.

[0100]

[0101] The amine-modified organic pigments and unmodified organic pigments obtained in each example and comparative example were evaluated by the following method. 2. Evaluation of self-dispersibility in PMA PMA (propylene glycol monomethyl ether acetate) was used as the organic solvent, and the dispersibility was evaluated by the following method. The solid material obtained after the drying step in each example and comparative example (powder in Comparative Examples 3-4) was mixed with the organic solvent to a concentration of 1% by weight (based on solid content), and 1 g of this mixture was dropped onto a glass plate and visually checked whether it aggregated or was homogeneous. - Uniformly dispersed and homogeneous with the solvent in appearance: ○ - Aggregates of organic pigment visible in appearance: × The results are shown in Table 8.

[0102] For those samples that received a "○" in the above dispersibility evaluation, the particle size D50 was measured using a particle size distribution analyzer (NanoTrack WAVE II, manufactured by MicroTrack Bell Co., Ltd.) after diluting them with PMA to the required range of reflected light intensity for the analyzer. The results are shown in Tables 8 and 9. In Examples 1 to 21, amine-modified organic pigments that self-disperse in PMA were obtained in all cases. In contrast, Comparative Examples 1 to 16 showed poor dispersion in PMA.

[0103]

[0104]

[0105] 3. Evaluation of solubility and self-dispersibility in various organic solvents and monomers Using the same method as in "Evaluation of PMA solubility of amine compounds" above, amine compound 2 was evaluated for solubility using toluene, MEK (methyl ethyl ketone), and butyl acetate instead of PMA. The solubility evaluation was good in all solvents. Using toluene, MEK, and butyl acetate as organic solvents, the dispersibility of the amine-modified organic pigment of amine compound 2 obtained in Example 11 was evaluated in the same manner as in "1. Evaluation of self-dispersibility in PMA" above. The results showed good dispersibility in all organic solvents. Furthermore, the dispersed particle size of the amine-modified organic pigment obtained in Example 11 in each of these organic solvents was measured using the same method as in "2. Measurement of dispersed particle size" above. The D50 particle size was 129 nm in toluene, 132 nm in MEK, and 121 nm in butyl acetate.

[0106] Using the method described above for "Evaluation of PMA solubility of amine compounds," when amine compound 3 was used with MEK (methyl ethyl ketone), IPA (isopropyl alcohol), NMP (N-methyl-2-pyrrolidone), and BZA (benzyl acrylate, acrylic monomer, manufactured by Osaka Organic Chemical Industry Co., Ltd., Viscoat #160) as monomers, and water instead of PMA, the solubility evaluation was good in all solvents. Using MEK, IPA, NMP as organic solvents, benzyl acrylate (Viscoat #160, manufactured by Osaka Organic Chemical Industry Co., Ltd.) as monomers, and water, the dispersibility of the amine-modified organic pigment using amine compound 3 obtained in Example 17 was evaluated in the same manner as described above in "1. Evaluation of self-dispersibility in PMA." As a result, the dispersibility was good in all organic solvents. Furthermore, when the dispersed particle size of the amine-modified organic pigment obtained in Example 17 was measured in each of these organic solvents using the same method as described in "2. Measurement of Dispersed Particle Size" above, the D50 particle size was 83 nm in MEK, 79 nm in IPA, 90 nm in NMP, 84 nm in benzyl acrylate, and 83 nm in water.

[0107] 4. Discussion As can be seen from Comparative Examples 1 and 2, when using organic pigments other than water-dispersible organic pigments, it is not possible to obtain amine-modified organic pigments that disperse easily in organic solvents. In contrast, in Examples 1 to 19, which used water-dispersible organic pigments, self-dispersibility in organic solvents was observed, indicating that they were modified with amines.

[0108] As shown in Table 8, aggregates of organic pigments were observed in Comparative Examples 3 and 4, which did not use amine compounds, indicating that self-dispersibility in organic solvents was not achieved. In contrast, in Examples 1 to 19, which used amine compounds, self-dispersibility in organic solvents was demonstrated.

[0109] As shown in Table 8, in Comparative Examples 7 and 13, which used amine compounds with an amine value exceeding 120 mg KOH / g and insoluble in PMA, aggregates of organic pigments were observed, indicating a lack of self-dispersibility in organic solvents. In contrast, in Examples 1 to 19, which used amine compounds with an amine value of 10 to 120 mg KOH / g and soluble in PMA, self-dispersibility in organic solvents was observed. As shown in Table 8, in Comparative Examples 9 and 15, which used compound 1 without an amine, aggregates of organic pigments were observed, indicating a lack of self-dispersibility in organic solvents. In contrast, in Examples 1 to 19, which used amine compounds, self-dispersibility in organic solvents was observed. As shown in Table 8, in Comparative Examples 5 and 11, which used amine compounds of non-cyclic tertiary amines, and Comparative Examples 6 and 12, which used amine compounds of quaternary ammonium salts, aggregates of organic pigments were observed, indicating a lack of self-dispersibility in organic solvents. In contrast, in Examples 1 to 19, which used amine compounds of primary amines, secondary amines, and cyclic amines, self-dispersibility in organic solvents was observed.

[0110] Amine compound 11 has a weight molecular weight of 100,000 and a weight-average molecular weight exceeding 50,000. As shown in Table 8, in Comparative Examples 8 and 14 using this amine compound, aggregates of organic pigments were observed, indicating that self-dispersibility in organic solvents was not achieved. In contrast, in Examples 1 to 19, which used amine compounds with weight-average molecular weights of 5,000 to 50,000, and especially 1,000 to 30,000, self-dispersibility in organic solvents was observed.

[0111] Tables 10 and 11 show the parts by weight of the amine compound per 100 parts by weight of the pigment, and the number of moles of amino groups of the amine compound relative to the calculated number of moles of hydrophilic functional groups introduced on the surface of the pigment (percentage). As shown in Table 10, when the amount of amine compound 1 is 20 parts by weight per 100 parts by weight of the pigment, and the ratio of the number of moles of amino groups of the amine compound to the number of moles of sulfone groups on the surface of the organic pigment (calculated assuming that all sulfone groups of the compound used in the reaction have been introduced; the same applies hereinafter) is low, with the number of moles of amino groups of the amine relative to the number of moles of sulfone groups being 51% (Comparative Example 10) and 15% (Comparative Example 16), aggregates of the organic pigment are observed, and self-dispersibility in the organic solvent is not obtained. On the other hand, when the amount of amine compound 1 is 200 parts by weight relative to the pigment, and the number of moles of amino groups of the amine compound relative to the number of moles of sulfone groups on the surface of the organic pigment is 100% or more, such as 515% (Example 1) and 154% (Example 15), self-dispersibility in the organic solvent is observed. In Comparative Examples 10 and 16, the large amount of hydrophilic functional groups on the surface of the organic pigment that have not reacted with the amine compound suggests that dispersion in an organic solvent is difficult.

[0112]

[0113]

[0114] Examples 5, Comparative Example 17, and Comparative Example 19 differ only in the dispersion medium used when attempting modification by adding the amine compound. In Example 5, the liquid medium used when adding the amine compound was water, but as a result, there is a difference in whether or not aggregation occurs, as shown in Table 9. The reason why aggregation did not occur in Example 5 is thought to be that the amine compound reacted with the hydrophilic functional groups on the pigment surface, modifying the pigment surface with amine and imparting dispersibility to PMA. Therefore, these results show that the present invention allows the amine compound to be bonded to the organic pigment by mixing a hydrophilic organic pigment having hydrophilic functional groups on its surface with an amine compound in an aqueous medium, and furthermore, self-dispersibility is imparted, allowing for uniform dispersion in various liquid media without the addition of a dispersant. Similar results were obtained from comparing Example 6 with Comparative Examples 18 and 20, and from comparing Example 16 with Comparative Examples 21 and 23, demonstrating the superiority of the present invention. Furthermore, Comparative Examples 17 and 19 increased the amount of amine compared to Comparative Examples 18 and 20, respectively, but aggregation was still not resolved. Therefore, it can be seen that aggregation will not be resolved even if the amount of amine is increased unless the reaction is carried out in an aqueous medium. Comparative Examples 22 and 24 had increased amounts of amine compared to Comparative Examples 21 and 23, respectively, but aggregation was still not resolved. Therefore, this result also shows that aggregation will not be resolved even if the amount of amine is increased unless the reaction is carried out in an aqueous medium.

[0115] Examples 20-25 and Comparative Example 25 varied the ratio of water to PMA and the total volume of the combined water and PMA liquid, but only Comparative Example 25 showed aggregation. Similarly, Examples 26-27 and Comparative Examples 26-27 varied the ratio of water to ethanol and the total volume of the combined water and ethanol liquid, but only Comparative Examples 26-27 showed aggregation. On the other hand, Comparative Examples 25-26 and Example 28, and Comparative Example 27 and Example 29 kept the total volume of the liquid the same, only varying the ratio of water to PMA and ethanol, but no aggregation was observed in Examples 28-29. These results also show that, by mixing a hydrophilic organic pigment having hydrophilic functional groups on its surface with an amine compound in an aqueous medium containing at least 30% water, the amine compound can be bonded to the organic pigment, and furthermore, self-dispersibility is imparted, allowing for uniform dispersion in various liquid media without the addition of a dispersant.

[0116] Thus, from the viewpoint of dispersibility in organic solvents, it is clear that by reacting an amine compound with an amount greater than the amount of hydrophilic functional groups such as sulfone groups and / or carboxyl groups introduced on the surface of the organic pigment, the affinity to organic solvents can be increased and a good dispersion state of the organic pigment can be obtained without the need for a dispersant.

[0117] The organic pigment was added to an organic solvent or monomer at a 1% concentration in solid form and evaluated by stirring with a stirrer. It was found that the amine-modified organic pigment of the present invention became uniform through this process alone, and moreover, the dispersed particle size D50 was small and uniform to 300 nm or less. In particular, in Example 17, in which amine compound 3 was used as the amine compound, it was found that self-dispersibility was obtained in various solvents and monomers such as PMA, MEK, IPA, NMP, water, and BZA. Therefore, it was found that by selecting an amine compound considering its affinity for the solvent in which the organic pigment is dispersed, effective dispersibility in the desired organic solvent can be obtained.

[0118] In contrast, the organic pigments in the comparative examples can be visually observed to be aggregated under these conditions. As mentioned earlier, in the case of conventional organic pigments like these comparative examples, it is necessary to add a dispersant and then disperse them using dispersion equipment such as a bead mill or roll mill in order to achieve a comparable particle size level.

[0119] As can be seen from the above examples, the manufacturing method of the present invention allows for the bonding of a wide range of amine compounds to organic pigments through a simple reaction in an aqueous medium, and the resulting amine-modified organic pigments can self-disperse in various organic solvents and monomers.

[0120] Furthermore, as mentioned above, when using amine compounds of non-cyclic tertiary amines and quaternary ammonium salts, self-dispersibility in organic solvents was not achieved, whereas when using amine compounds of primary amines, secondary amines, and cyclic amines, self-dispersibility in organic solvents was observed. From this, it can be concluded that primary amines, secondary amines, and cyclic amines with bonding bonds chemically bond with the hydrophilic functional groups of organic pigments, thereby imparting the organic solvent affinity of the amine compounds to the organic pigments.

[0121] As described above, it can be seen that the amine-modified organic pigment according to the present invention can be uniformly dispersed in an organic solvent even without a dispersant.

[0122] The present invention makes it possible to obtain organic pigments that self-disperse in organic solvents without the need to add a dispersant.

Claims

1. A method for producing an amine-modified organic pigment, characterized by mixing a hydrophilic organic pigment having hydrophilic functional groups on its surface with an amine compound in an aqueous medium to bond the amine compound to the organic pigment, wherein the amine compound is a primary amine, a secondary amine, or a cyclic amine, and the amine compound has an amine value of 10 to 120 mg KOH / g and a weight-average molecular weight of 500 to 50,000, and the equivalent amount of the amine compound is equal to or greater than the equivalent amount of hydrophilic functional groups on the surface of the hydrophilic organic pigment.

2. The method for producing an amine-modified organic pigment according to claim 1, characterized in that the amine compound is soluble in one or more organic solvents selected from toluene, butyl acetate, and methyl ethyl ketone.

3. The method for producing an amine-modified organic pigment according to claim 1, characterized in that the amine compound is soluble in propylene glycol monomethyl ether acetate or benzyl acrylate.

4. A method for producing an amine-modified organic pigment according to claim 1, characterized in that an amine compound and an organic pigment are bonded via one or more of the following: -SO2NH-, -SO2N-, -CONH-, and -CON-.

5. The method for producing an amine-modified organic pigment according to claim 1, wherein the amine portion of the amine compound is one or more of cyclic imides, oxazolines, or imidazolidinones.

6. An amine-modified organic pigment, characterized in that a hydrophilic functional group is introduced into the organic pigment and the amine compound is bonded to the organic pigment by mixing it with an amine compound in an aqueous medium, wherein the amine compound has an amine value of 10 to 120 mg KOH / g and a weight-average molecular weight of 500 to 50,000, and the blending ratio of the organic pigment to the amine compound is 1 to 500 parts by weight of the amine compound in terms of solid content per 100 parts by weight of the organic pigment.

7. An amine-modified organic pigment in which an amine compound is bonded to an organic pigment, characterized in that (i) the amine compound is bonded to the organic pigment via one or more of the following: -SO2NH-, -SO2N-, -CONH-, and -CON-; (ii) the amine value including the amine value of the bonded portion to the organic pigment is 10 to 120 mgKOH / g; and (iii) the amine compound has a molecular weight of 500 to 50,000.

8. The amine-modified organic pigment according to claim 6 or 7, characterized in that the amine compound is soluble in one or more organic solvents selected from toluene, butyl acetate, and methyl ethyl ketone.

9. The amine-modified organic pigment according to claim 6 or 7, characterized in that the amine compound is soluble in propylene glycol monomethyl ether acetate or benzyl acrylate.

10. The amine-modified organic pigment according to claim 6 or 7, wherein the amine portion of the amine compound is one or more of cyclic imides, oxazolines, or imidazolidinones.

11. A dispersion of amine-modified organic pigments, wherein the amine-modified organic pigment according to claim 6 or 7 is dispersed in an organic solvent.

12. A coloring composition containing the amine-modified organic pigment according to claim 6 or 7.

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