Mixed crystal composition of quinacridone and diketopyrrolopyrrole and method for producing same

Abstract

This application describes a method for producing a mixed crystal pigment composition in a one-step solvent-salt-kneading process, which is a magenta pigment consisting of mixed crystals of two quinacridones (PV19 and PR122) in a physical mixture with at least one diketopyrrolopyrrole.

Description

[Technical field]

[0001] The present invention relates to a mixed crystal composition of quinacridone and diketopyrrolopyrrole and a method for preparing the same. [Background technology]

[0002] The cited document does not mention the composition of the product of the present application, nor does it mention the target properties (hue, color intensity, transparency).Furthermore, the cited document does not mention the overall composition, as well as the use of a solvent-salt-kneading process for the preparation of mixed crystals.

[0003] All of the literature that refers to the production of solid solutions or mixed crystals by co-synthesis requires additional finishing steps (e.g., grinding, solvent finishing, blending) to obtain the pigment material. The multiple handling steps require increased production time and energy output. Furthermore, each processing step presents its own disadvantages in terms of process stability. By reducing the processing steps to a single step, the process becomes more efficient, faster, and less unstable in terms of product quality.

[0004] None of the documents mentions a chlorine-free alternative that matches the compositions of the present application.

[0005] The printing industry mostly uses four process colours in its inks: cyan, magenta, yellow and black (CMYK). In recent years, there has been an increasing demand for halogen-free alternatives to established standard pigments in order to prevent the release of halogens into the environment, e.g. during incineration at the end of the life cycle of printed materials. For yellowish magenta there are particular challenges, as the widely established pigments either contain halogen atoms (PR48:2, PR48:8, PR146) or have low colour strength (PV19, mixed crystals of PV19 and PR122), making them of low use value or high opacity.

[0006] PV19 is 5,12-dihydroquinolino[2,3-b]acridine-7,14-dione (CIPV19, CAS 1047-16-1).PR122 is 2,9-dimethyl-5,12-dihydroquinolino[2,3-b]acridine-7,14-dione (CIPR122, CAS 980-26-7).

[0007] It is known that PV19 and PR122 can be synthesized by co-cyclization of diarylaminoterephthalic acid and dialkylarylaminoterephthalic acid in pholyphosphoric acid to form mixed crystals in ratios of 85:15 to 60:40. However, this co-synthesis only produces crude pigments and requires additional finishing steps to produce useful pigments (e.g. EP3778784A1). This approach results in magentas with weak color intensity and / or too blue in hue.

[0008] Through research, it has been found that the mixed crystals of PV19 and PR122 currently available on the market do not meet the requirements for color strength and hue.Surprisingly, it has been found that by forming a physical mixture of DPP (diketopyrrolopyrrole) (color index PR264 or PR272) and optionally a synergist, such as a quinacridone pigment derivative, such as a monosulfonic acid metal salt derivative of PV19, and the mixed crystals of PV19+PR122 by solvent-salt-kneading, a chlorine-free yellowish magenta with high transparency and color strength can be achieved.

[0009] PR264 is 3,6-bis-biphenyl-4-yl-2,5-dihydropyrrolo[3,4-c]pyrrole-1,4-dione (CIPR264, CAS 88949-33-1).PR272 is 3,6-bis(4-methylphenyl)-2,5-dihydropyrrolo[3,4-c]pyrrole-1,4-dione (CIPR272, CAS 84632-66-6).

[0010] It is well known that quinacridones can form solid solutions or mixed crystals by co-synthesis in polyphosphoric acid process or by wet grinding. However, co-synthesis only gives crude pigments, and further finishing steps are required to produce useful pigments. In this approach, it is difficult to control particle size and morphology. Moreover, when the co-synthesis approach is already carried out with nucleophilic substitution of dialkyl succinates with aniline derivatives, as in US2005011403A1, asymmetric QA (quinacridone) is formed, which requires cumbersome global registration of CIPR282. Moreover, when solid solutions or mixed crystals are produced by co-synthesis, it becomes difficult to control the specific ratio of each component, since the yields of each synthesis are different. [Prior art documents] [Patent documents]

[0011] [Patent Document 1] EP3778784A1 [Patent Document 2] US2005011403A1 Summary of the Invention [Problem to be solved by the invention]

[0012] The method of the present invention is advantageous in that mixed crystals can be formed from crude pigments of the individual components (PV19 and PR122) by solvent-salt-kneading. Solvent-salt-kneading serves as a grinding technique to reduce particle size and at the same time allows for crystal regrowth in a suitable solvent system. We have found that vigorously mixing the individual components together promotes the formation of solid solution / mixed crystals. The parameters that affect the particle size during the solvent-salt-kneading process are known to those skilled in the art and can be easily adjusted to adjust the particle size and therefore the properties of the resulting pigment.

[0013] In one embodiment, the crude pigments of the individual components (PV19 and PR122) comprise pigments of the individual components (PV19 and PR122) obtained from a synthesis of the individual components (PV19 and PR122), preferably obtained from a synthesis without a finishing step, the finishing step preferably comprising a modification selected from the group consisting of a particle size modification and a surface modification.

[0014] For the purposes of this application, a solid solution is defined as a crystalline material consisting of a host compound and one or more guest compounds incorporated into the crystal lattice of the host. Thus, the solid solution is characterized by the crystal lattice of the host. Furthermore, for the purposes of this application, a mixed crystal is defined as a crystalline material consisting of two or more compounds that exhibits a crystal lattice different from that of the individual components (High Performance Pigments, edited by Hugh M. Smith, p. 296, Wiley-VCH Verlag-GmbH, 2002, ISBN3-527-30204-2).

[0015] Both solid solutions and mixed crystals can be characterized, for example, by powder X-ray diffraction. For the purposes of this application, mixed crystals can be considered a type of solid solution.

[0016] The crude materials used in the solvent-salt-kneading process to form the mixed crystals can be synthesized separately, thus eliminating the need for co-synthesis. Because the solvent-salt-kneading process involves a simultaneous grinding and regrowth process, pre-grinding of the materials is not required, and crude large particle materials can be utilized. Another advantage is that additional components can be easily added to the product (PR264, PR272, or any QA (quinacridone) synergist, DPP (diketopyrrolopyrrole) synergist, resin, or additive) by introducing the materials into the solvent-salt-kneading process before, during, and / or after the formation of the QA (quinacridone) mixed crystals. The added materials can be easily incorporated into the product and help to adjust the color properties and secondary properties (rheology, durability) of the product. Thus, compared to the conventional methods that involve multiple processes (grinding, solvent finishing, blending, etc.), the approach of the present invention functions as a one-step process.

[0017] In one embodiment, the crude material used in the solvent-salt-kneading process consists of the material obtained from the synthesis of the individual materials, preferably the synthesis without a finishing step, which preferably includes a modification selected from the group consisting of particle size modification and surface modification.

[0018] In a further embodiment, the crude large particle material comprises material obtained from synthesis of the individual components, preferably without a finishing step, the finishing step preferably comprising a modification selected from the group consisting of particle size modification and surface modification.

[0019] Solvent-salt-kneading is a very versatile method for producing solid solutions or mixed crystals, as it can be easily adapted to different chemistries without the need for co-synthesis.

[0020] Solvent-salt-kneading promotes the formation of solid solutions or mixed crystals while simultaneously polishing the material to optimal particle size and size distribution by grinding and regrowth. Thus, solvent-salt-kneading is a one-step process (mixed crystal formation + polishing) compared to state-of-the-art multi-step processes that require mixed crystal formation followed by grinding, polishing and blending steps.

[0021] Pigments finished in such a one-step procedure exhibit more uniform particle size for both the mixed crystal components and the physical mixture components, and thus exhibit equal or very similar dispersion characteristics for each of the components, which is highly advantageous for color matching compared to paints / inks prepared by blending multiple components into a millbase (e.g. EP3480264B1).

[0022] The composition distinguishes itself from the industry standard because it is a halogen-free yellowish magenta with excellent color strength and clarity -- no other pigment on the market has these characteristics.

[0023] Citation or identification of a document in this application is not an admission that it is prior art to the present invention.

[0024] This application describes a one-step solvent-salt-kneading process for producing a magenta pigment consisting of mixed crystals of two quinacridones (PV19 and PR122). In the resulting composition, the magenta pigment is further contained in a physical mixture with at least one diketopyrrolopyrrole (Pigment Red 264 and Pigment Red 272) in a ratio of 60:40 to 85:15 or 60:40 to 75:25, which represents 1 to 15% by weight or 4 to 10% by weight of the total composition. The composition may further optionally contain 0 to 15% of a quinacridone synergist, such as a monosulfonic acid metal salt derivative of PV19. The composition is advantageously produced in a one-step process by solvent-salt-kneading.

[0025] It is known that yellowish magenta ("process red" colors) are mostly composed of azo pigments (e.g. PR57:1; PR48:2; PR146, PR269) and do not match the excellent properties of high performance pigments such as quinacridone or diketopyrrolopyrrole. Moreover, among the mentioned azo pigments, only PR57:1 does not contain chlorine. Thus, the present composition formed by the solvent-salt-kneading process offers a unique chlorine-free high performance alternative to azo pigments in the field of "process red" colors for printing applications. Quinacridone-based magentas, such as PV19 or mixed crystals of PV19 and PR122, are chlorine-free and considered high performance pigments, but cannot meet the requirements regarding hue, transparency and color strength.

[0026] In the present invention, the quinacridone mixed crystal refers to a quinacridone mixed crystal containing PV19 and PR122 as essential components, more specifically, a quinacridone solid solution in which a mixed crystal phase of PR122 and PV19 is formed. Therefore, this mixed crystal has unique peaks at diffraction angles of 5.9°±0.2° 2θ and 11.9°±0.2° measured by powder X-ray diffraction, which do not exist in either the single crystal of PV19 or the single crystal of PR122. Therefore, it is possible to easily confirm by crystal X-ray diffraction whether a quinacridone pigment is a mixed crystal or a simple mixture of single crystals.

[0027] The compositions of the present application further contain either PR264 or PR272, and optionally a quinacridone synergist, such as a monosulfonate metal salt derivative of PV19, in a physical mixture with the mixed crystals described above. The presence of either can be determined, for example, by mass spectrometry.

[0028] The compositions of the present invention may be advantageously prepared by solvent-salt-kneading, which facilitates the formation of quinacridone mixed crystals by vigorous intermixing with successive grinding and regrowth during the process.

[0029] The solvent-salt-kneading is carried out using an organic solvent such as one or more of ethylene glycol, diethylene glycol, diacetone alcohol, dimethylformamide, glycerin, triethylene glycol, dipropylene glycol, ethylene glycol monobutyl ether, methyl ethyl ketone, cyclohexanone, dimethylacetamide, N-methylpyrrolidone, butyl acetate, glycerol triacetate, sulfolane, xylene, tetrahydrofuran, butanol, water, and dimethyl sulfoxide. In one embodiment, the at least one solvent comprises one or more of diethylene glycol, diacetone alcohol, and glycerin. In one embodiment, the at least one solvent is diethylene glycol.

[0030] In one embodiment of the present invention, the addition of one or more quinacridone synergists is optionally included, such as sulfonic acid derivatives and / or salts of quinacridone; formaldehyde reaction products of 5,12-dihydroquino[2,3-b]acridine-7,14-dione and 3,5-dimethyl-1H-pyrazole, formaldehyde reaction products of 5,12-dihydroquino[2,3-b]acridine-7,14-dione and 3,5-dimethyl-1H-pyrazole, sulfonated or 2-[(1,3-dihydro-1,3-dioxo-2H-isoindol-2-yl)methyl]-5,12-dihydroquino[2,3-b]acridine-7,14-dione.

[0031] In one embodiment of the present invention, the addition of one or more synergists will be included, optionally, such as natural or synthetic resins including esters and salts of abietic acid, hydrogenated or partially hydrogenated or dimerized rosins, non-ionic surfactants of the polysorbate type including esters or mixtures of esters formed from fatty acids, such as lauric acid or sebacic acid, and polyols such as sorbitin monolaurate or dibutyl sebacate. The synergists may be added either before and / or during and / or after kneading and / or grinding.

[0032] In the powder X-ray diffraction pattern, the mixed crystals of PR122 and PV19 show two signals at 5.9°±0.2° 2θ and 11.9°±0.2° 2θ, which are not present in the diffraction patterns of the individual components, nor in the lattice of a typical commercial PR122 solid solution, e.g. Hostaperm Pink E (Heubach). These signals are well separated from the other signals in the diffraction pattern and are therefore ideal for characterizing the mixed crystals.

[0033] The successful formation of mixed crystals can be assessed by the intensity ratio of the two signals.

[0034] Intensity ratio=(diffraction peak intensity when the diffraction angle 2θ is around 5.9°) / (diffraction peak intensity when the diffraction angle 2θ is around 11.9°)>3.

[0035] Thus, when a DPP (diketopyrrolopyrrole) component is added to the solvent salting out of the QA (quinacridone) mixed crystals, a physical mixture of the mixed crystals and DPP (diketopyrrolopyrrole) is formed. This is evidenced by PXRD (powder X-ray diffraction) where the diffraction pattern resembles a superposition of the diffraction pattern of the QA (quinacridone) mixed crystals and the diffraction patterns of the individual DPP components. As an example, the addition of DPP results in additional signals at 8.0°±0.2° 2θ and 17.9°±0.2° 2θ (PR264), or at 7.7°±0.2° 2θ and 15.7°±0.2° 2θ (PR272).

[0036] Solvent-salt-kneading uses an inorganic salt as the grinding medium, such as sodium chloride, sodium sulfate, or anhydrous aluminum sulfate or mixtures thereof. In one embodiment, the pigment to salt ratio is between 1:3 and 1:18. In another embodiment, it is between 1:4 and 1:12. In another embodiment, it is between 1:6 and 1:8. Solvent-salt-kneading is advantageously carried out at a temperature between 25° C. and 120° C., such as between 40° C. and 100° C., or between 60° C. and 80° C. Solvent-salt-kneading is typically carried out for a period of 4 hours to 48 hours, such as between 6 hours to 24 hours, or between 8 hours to 18 hours.

[0037] During the solvent-salt-kneading process the pigment is formed as crystalline particles with a particle size Dv(50)<150 nm. Preferably the pigment has a particle size distribution Dv(50) in the range of 10-145 nm, more preferably 20-140 nm, more preferably 25-130 nm, more preferably 30-120 nm. Even with rather large particle sizes the individual crude components can result in a product with excellent color properties.

[0038] According to the method of the present invention, the mixed crystal quinacridone pigment composition has a particle size distribution with Dv(50)<150 nm, and preferably, the mixed crystal quinacridone pigment composition has a particle size distribution with Dv(50) determined according to Reference Example 5 in the range of 10 to 145 nm, more preferably 20 to 140 nm, more preferably 25 to 130 nm, more preferably 30 to 120 nm.

[0039] Further in accordance with the method of the present invention, the method further comprises milling the crude quinacridone pigment in the presence of a diketopyrrolopyrrole selected from the group consisting of PR264, PR272 and mixtures thereof.

[0040] According to the method of the present invention, PV19 is 5,12-dihydroquinolino[2,3-b]acridine-7,14-dione, and / or PR122 is 2,9-dimethyl-5,12-dihydroquinolino[2,3-b]acridine-7,14-dione, and / or PR264 is 3,6-bis-biphenyl-4-yl-2,5-dihydropyrrolo[3,4-c]pyrrole-1,4-dione, and / or PR272 is 3,6-bis(4-methylphenyl)-2,5-dihydropyrrolo[3,4-c]pyrrole-1,4-dione.

[0041] According to the method of the present invention, the one-step solvent-salt-kneading process is a solvent-salt-kneading process.

[0042] According to the method of the present invention, in (a), the crude quinacridone pigment comprises a pigment obtained from a synthesis of a quinacridone pigment, preferably obtained from a synthesis without a finishing step, the finishing step preferably comprising a modification selected from the group consisting of a particle size modification and a surface modification.

[0043] According to the method of the present invention, in (a), the temperature is in the range of 60 to 90°C, preferably 40 to 90°C, more preferably 80 to 90°C, or the temperature is in the range of 45 to 100°C, preferably 50 to 90°C.

[0044] According to the process of the present invention, in (a)(i), the inorganic salt is selected from the group consisting of alkali metal halides, alkali metal sulfates, alkaline earth metal halides, alkaline earth metal sulfates, and mixtures of two or more thereof, preferably, the inorganic salt is selected from the group consisting of sodium chloride, sodium sulfate, anhydrous aluminum sulfate, and mixtures of two or more thereof, more preferably, the inorganic salt is sodium chloride.

[0045] According to the method of the present invention, in (a)(ii), the solubility of the crude quinacridone pigment and the salt in the organic liquid is in the range of 0 to 10 g / L, preferably 0.0001 to 9.5 g / L, and more preferably 0.0005 to 9 g / L at a temperature in the range of 20 to 25° C.

[0046] In (a)(ii) of any method of any preceding paragraph, the salt comprises an inorganic salt.

[0047] According to the method of the present invention, the mixed crystal quinacridone pigment composition contains a quinacridone synergist, and 0 to 10% by weight of the mixed crystal quinacridone pigment composition consists of the quinacridone synergist.

[0048] According to the method of the present invention, the particle size distribution Dv(50) is determined according to Reference Example 5.

[0049] According to the method of the present invention, in (c), the quinacridone pigment has a particle size distribution, Dv(50), determined according to Reference Example 5, in the range of 10 to 145 nm, preferably 20 to 140 nm, more preferably 25 to 130 nm, more preferably 30 to 120 nm.

[0050] According to the process of the present invention, in (a)(ii) the organic liquid comprises a solvent.

[0051] In one embodiment, the crude components include those components obtained in the synthesis of the individual components, preferably obtained from a synthesis without a polishing step, the polishing step preferably including a modification selected from the group consisting of a particle size modification and a surface modification.

[0052] The present invention is further illustrated by the following numbered clauses, which represent a series of embodiments and combinations of embodiments resulting from the indicated dependencies and back references. In particular, in each instance where a range of embodiments is mentioned, it is to be noted that in the context of a term such as "any one of the methods of embodiments 1 to 5", all embodiments within this range are expressly disclosed to those skilled in the art, i.e., the expression of this term is understood by those skilled in the art to be equivalent to "any one of the methods of embodiments 1, 2, 3, 4 and 5". Furthermore, it is to be expressly noted that the following series of embodiments represents a suitably constructed part of the description directed to the general and preferred aspects of the present invention, rather than a series of claims determining the scope of protection. [Means for solving the problem]

[0053] 1. A method for producing a mixed crystal quinacridone pigment composition comprising a one-step solvent-salt-knead process comprising the steps of: (a) subjecting a crude quinacridone pigment to a process comprising the steps of: (i) an inorganic salt in the range of about 3 to about 12 parts by weight based on the crude quinacridone pigment; (ii) an organic liquid in which the crude quinacridone pigment and the salt are substantially insoluble, and (iii) optionally, a quinacridone synergist; grinding in the presence of (b) discharging the crude quinacridone pigment from step (a) into water, thereby obtaining a water-pigment mixture; and (c) isolating a quinacridone pigment having a particle size distribution of Dv(50)<150 nm from the mixture. The method includes:

[0054] 2. The method of item 1, wherein the composition comprises a combination of PV19 and PR122, preferably the composition is a combination of PV19 and PR122.

[0055] 3. The method according to item 2, further comprising a diketopyrrolopyrrole selected from the group consisting of PR264, PR272 or both in an amount of 0.1 to 15% by mass, 1 to 15% by mass, or 5 to 10% by mass of the total composition.

[0056] 4. The method according to item 2, wherein PV19 and PR122 are present in a ratio of 60:40 to 85:15 or 60:40 to 75:25.

[0057] 5. The method of any preceding paragraph, wherein the mixed crystal quinacridone pigment composition has a particle size distribution with Dv(50)<150 nm, preferably the mixed crystal quinacridone pigment composition has a particle size distribution with Dv(50) determined according to Reference Example 5 in the range of 10 to 145 nm, more preferably 20 to 140 nm, more preferably 25 to 130 nm, more preferably 30 to 120 nm.

[0058] 6. The method of any preceding claim, wherein (a) further comprises milling the crude quinacridone pigment in the presence of a diketopyrrolopyrrole selected from the group consisting of PR264, PR272, and mixtures thereof.

[0059] 7. The method of any preceding claim, wherein PV19 is 5,12-dihydroquinolino[2,3-b]acridine-7,14-dione, and / or PR122 is 2,9-dimethyl-5,12-dihydroquinolino[2,3-b]acridine-7,14-dione, and / or PR264 is 3,6-bis-biphenyl-4-yl-2,5-dihydropyrrolo[3,4-c]pyrrole-1,4-dione, and / or PR272 is 3,6-bis(4-methylphenyl)-2,5-dihydropyrrolo[3,4-c]pyrrole-1,4-dione.

[0060] 8. The method of any preceding claim, wherein the one-step solvent-salt-kneading process is a solvent-salt-kneading process.

[0061] 9. The method of any preceding claim, wherein in (a), the crude quinacridone pigment comprises a pigment obtained from a synthesis of a quinacridone pigment, preferably obtained from a synthesis without a finishing step, the finishing step preferably including a modification selected from the group consisting of a particle size modification and a surface modification.

[0062] 10. Any process of any preceding paragraph, wherein in (a) the temperature is in the range of 60 to 90°C, preferably 40 to 90°C, more preferably 80 to 90°C, or the temperature is in the range of 45 to 100°C, preferably 50 to 90°C.

[0063] 11. Any of the process of any preceding clause, wherein in (a)(i) the inorganic salt is selected from the group consisting of alkali metal halides, alkali metal sulfates, alkaline earth metal halides, alkaline earth metal sulfates, and mixtures of two or more thereof; preferably the inorganic salt is selected from the group consisting of sodium chloride, sodium sulfate, anhydrous aluminum sulfate, and mixtures of two or more thereof; more preferably the inorganic salt is sodium chloride.

[0064] 12. The method of any preceding claim, wherein in (a)(ii), the solubility of the crude quinacridone pigment and salt in the organic liquid is in the range of 0 to 10 g / L, preferably 0.0001 to 9.5 g / L, more preferably 0.0005 to 9 g / L at a temperature in the range of 20 to 25° C.

[0065] 13. Any process of any preceding paragraph, wherein in (a)(ii) the salt comprises an inorganic salt.

[0066] 14. The method of any preceding paragraph, wherein the mixed crystal quinacridone pigment composition comprises a quinacridone synergist, and wherein from 0 to 10 weight percent of the mixed crystal quinacridone pigment composition consists of the quinacridone synergist.

[0067] 15. Any method of any preceding paragraph, wherein the particle size distribution Dv(50) is determined according to Example 5.

[0068] 16. Any method of any preceding paragraph, wherein in (c), the quinacridone pigment has a particle size distribution, determined according to Reference Example 5, of Dv(50) in the range of 10 to 145 nm, preferably 20 to 140 nm, more preferably 25 to 130 nm, more preferably 30 to 120 nm.

[0069] 17. The method of any preceding claim, wherein in (a)(ii) the organic liquid comprises a solvent.

[0070] 18. The method of any preceding clause, comprising a solvent selected from the group consisting of ethylene glycol, diethylene glycol, diacetone alcohol, dimethylformamide, glycerin, triethylene glycol, dipropylene glycol, ethylene glycol monobutyl ether, methyl ethyl ketone, cyclohexanone, dimethylacetamide, N-methylpyrrolidone, butyl acetate, glycerol triacetate, sulfolane, xylene, tetrahydrofuran, butanol, water, dimethylsulfoxide, and blends thereof, preferably the solvent is selected from the group consisting of ethylene glycol, diethylene glycol, diacetone alcohol, dimethylformamide, glycerin, triethylene glycol, dipropylene glycol, ethylene glycol monobutyl ether, methyl ethyl ketone, cyclohexanone, dimethylacetamide, N-methylpyrrolidone, butyl acetate, glycerol triacetate, sulfolane, xylene, tetrahydrofuran, dimethylsulfoxide, and mixtures of two or more thereof.

[0071] 19. The method of claim 18, wherein the at least one solvent comprises one or more of diethylene glycol, diacetone alcohol, and glycerin, preferably the solvent is diethylene glycol.

[0072] 20. The method of any preceding claim, wherein the synergist is a quinacridone derivative selected from the group consisting of quinacridone sulfonic acids and their salts, phthalimidoalkyl-quinacridones, imidazolylalkyl-quinacridones, pyrazolylalkyl-quinacridones, sulfonic acids and their salts of pyrazolylalkyl-quinacridones, and dialkylaminoalkylsulfonamide derivatives of quinacridone.

[0073] 21. The synergist is selected from the group consisting of sulfonic acid derivatives and / or salts of quinacridone, quino[2,3-b]acridine-2-sulfonic acid, 5,7,12,14-tetrahydro-7,14-dioxo- and metal salts thereof, formaldehyde reaction products with 5,12-dihydroquino[2,3-b]acridine-7,14-dione and 3,5-dimethyl-1H-pyrazole, formaldehyde reaction products with 5,12-dihydroquino[2,3-b]acridine-7,14-dione and 3,5-dimethyl-1H-pyrazole, sulfonated or 2-[(1,3-dihydro-1,3- 13. The method of any preceding claim, wherein the surfactant is selected from the group consisting of: dioxo-2H-isoindol-2-yl)methyl-5,12-dihydroquino[2,3-b]acridine-7,14-dione, natural or synthetic resins including esters and salts of abietic acid, hydrogenated or partially hydrogenated or dimerized rosins, polysorbate type nonionic surfactants including esters or mixtures of esters formed from fatty acids, such as lauric acid or sebacic acid, polyols, such as sorbitan monolaurate or dibutyl sebacate, and blends thereof.

[0074] 22. The method of any preceding claim, wherein the synergist is present in an amount of 1 to 10% by weight based on the crude quinacridone pigment, preferably the (a)(iii) synergist is present in an amount of 1 to 10% by weight based on the crude quinacridone pigment of (a).

[0075] 23. The method of any preceding claim, wherein the synergist is present in an amount of 1 to 5% by weight based on the crude quinacridone pigment, preferably the (a)(iii) synergist is present in an amount of 1 to 5% by weight based on the crude quinacridone pigment of (a).

[0076] 24. The method of any preceding claim, wherein the synergist is present in the range of about 0.001 to about 0.1 parts by weight based on the crude quinacridone pigment, and preferably the (a)(iii) synergist is present in the range of about 0.001 to about 0.1 parts by weight based on the crude quinacridone pigment of (a).

[0077] 25. The method of any preceding claim, wherein the narrow particle size distribution obtained by Dv(50) is <150 nm, preferably the narrow particle size distribution obtained by Dv(50) is in the range of 10-145 nm, more preferably 20-140 nm, more preferably 25-130 nm, more preferably 30-120 nm, as determined according to Reference Example 5.

[0078] 26. The method of any preceding claim, wherein the composition is characterized by a powder X-ray diffraction signal at diffraction angles 2θ of about 5.9°±0.2° and 11.9°±0.2°.

[0079] 27. The method of claim 26, wherein the composition is further characterized by a powder X-ray diffraction signal after addition of PR264 at diffraction angles of 8.0°±0.2° 2θ and 17.9°±0.2° 2θ.

[0080] 28. The method of claim 26, wherein the composition is further characterized by a powder X-ray diffraction signal after addition of PR272 at diffraction angles of 7.7°±0.2° 2θ and 15.7°±0.2° 2θ.

[0081] 29. A mixed crystal quinacridone pigment composition resulting from the method according to any one or more of paragraphs 1 to 28.

[0082] 30. The pigment composition according to Item 29, wherein the ratio of the diffraction peak intensity at a diffraction angle 2θ of 5.9±0.2° to the diffraction peak intensity at a diffraction angle 2θ of 11.9±0.2° is 3 or more, and preferably the ratio of the diffraction peak intensity at a diffraction angle 2θ of 5.9±0.2° to the diffraction peak intensity at a diffraction angle 2θ of 11.9±0.2° is in the range of 3 to 20, more preferably 6 to 10, as measured by powder X-ray diffraction, and preferably the ratio of the diffraction peak intensities is measured according to Reference Example 4.

[0083] 31. The pigment composition according to item 29 or 30, wherein the amount of the quinacridone pigment derivative contained is 0.1 to 10 parts by mass per 100 parts by mass of the pigment, and preferably the amount of the quinacridone pigment derivative contained in (a)(iii) is 0.1 to 10 parts by mass per 100 parts by mass of the mixed crystal quinacridone pigment composition.

[0084] 32. The pigment composition according to item 29 or 30, wherein the amount of the quinacridone pigment derivative contained is 1 to 5 parts by mass per 100 parts by mass of the pigment, and preferably the amount of the quinacridone pigment derivative contained in (a)(iii) is 1 to 5 parts by mass per 100 parts by mass of the mixed crystal quinacridone pigment composition.

[0085] 33. The pigment composition according to item 29 or 30, wherein the amount of the quinacridone pigment derivative contained is 0.5 to 3 parts by mass, preferably 1 to 3 parts by mass, per 100 parts by mass of the pigment, and preferably the amount of the quinacridone pigment derivative contained in (a)(iii) is 0.5 to 3 parts by mass, preferably 1 to 3 parts by mass, per 100 parts by mass of the mixed crystal quinacridone pigment composition.

[0086] 34. The pigment composition according to any one or more of items 29 to 33, wherein the narrow particle size distribution obtained by Dv(50) is <150 nm, and preferably the narrow particle size distribution obtained by Dv(50) is in the range of 10 to 145 nm, more preferably 20 to 140 nm, more preferably 25 to 130 nm, and more preferably 30 to 120 nm, as determined according to Reference Example 5.

[0087] 35. The pigment composition according to any one or more of paragraphs 29 to 34, wherein the composition does not contain chlorine.

[0088] 36. A printing ink or coating or plastic composition comprising a pigment composition according to any one or more of paragraphs 29 to 35.

[0089] 37. A printing ink or coating composition according to paragraph 36, wherein the composition is suitable for use as a printing ink, automotive coating, architectural coating or industrial coating.

[0090] 38. The printing ink composition according to item 37, wherein the composition is suitable for use as a digital printing ink, an inkjet ink, an electrophotographic toner, a water-based ink, a UV-curable ink, a solvent-based ink or an oil-based ink.

[0091] 39. A printed or coated article comprising a printing ink or coating composition according to any one or more of paragraphs 35 to 38.

[0092] 40. The printed article of paragraph 39, wherein the article is a plastic article.

[0093] 41. A plastic article comprising a pigment composition according to any one or more of paragraphs 29 to 35.

[0094] The present invention further relates to a method for preparing a mixed crystal quinacridone pigment composition, the method comprising the steps of: (a) mixing at least two quinacridone pigments at a temperature in the range of 40 to 120° C. with one or more of the following: (i) an inorganic salt in an amount ranging from 3 to 12 parts by weight relative to the at least two quinacridone pigments; (ii) an organic liquid selected from the group consisting of ethylene glycol, diethylene glycol, diacetone alcohol, dimethylformamide, glycerin, triethylene glycol, dipropylene glycol, ethylene glycol monobutyl ether, methyl ethyl ketone, cyclohexanone, dimethylacetamide, N-methylpyrrolidone, butyl acetate, glycerol triacetate, sulfolane, xylene, tetrahydrofuran, dimethyl sulfoxide, and mixtures of two or more thereof; and (iii) 0 to 10% by mass of a synergist based on the mixed crystal quinacridone pigment composition grinding in the presence of (b) discharging the at least two milled quinacridone pigments from step (a) into water; and (c) isolating the at least two milled quinacridone pigments from step (b). Including, The milled at least two quinacridone pigments have a particle size distribution with a Dv(50) in the range of 10 to 145 nm. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0095] Preferably, the mixed crystal quinacridone pigment composition comprises PV19 and PR122.

[0096] Preferably, the at least two quinacridone pigments include PV19 and PR122.

[0097] PV19 and PR122 are preferably present in a ratio of 60:40 to 85:15 or 60:40 to 75:25.

[0098] Preferably, PV19 is 5,12-dihydroquinolino[2,3-b]acridine-7,14-dione and / or PR122 is 2,9-dimethyl-5,12-dihydroquinolino[2,3-b]acridine-7,14-dione.

[0099] It is preferred that the method further comprises a diketopyrrolopyrrole selected from the group consisting of PR264, PR272 and mixtures thereof, preferably PR264 is 3,6-bis-biphenyl-4-yl-2,5-dihydropyrrolo[3,4-c]pyrrole-1,4-dione and PR272 is 3,6-bis(4-methylphenyl)-2,5-dihydropyrrolo[3,4-c]pyrrole-1,4-dione.

[0100] When the method further comprises diketopyrrolopyrrole, the amount of diketopyrrolopyrrole ranges from 0.1 to 15% by weight, preferably 1 to 15% by weight, more preferably 5 to 10% by weight, based on the mixed crystal quinacridone pigment composition.

[0101] In (a), it is preferred that the at least two quinacridone pigments comprise at least two crude quinacridone pigments, the at least two crude pigments comprising at least two quinacridone pigments obtained from a synthesis of at least two quinacridone pigments, preferably obtained from a synthesis without a finishing step, the finishing step preferably comprising a modification selected from the group consisting of a particle size modification and a surface modification.

[0102] In (a), the temperature is in the range of 60 to 90°C, preferably 40 to 90°C, more preferably 80 to 90°C, or the temperature is in the range of 45 to 100°C, preferably 50 to 90°C.

[0103] In (a)(i), it is preferred that the inorganic salt is selected from the group consisting of alkali metal halides, alkali metal sulfates, alkaline earth metal halides, alkaline earth metal sulfates, and mixtures of two or more thereof; preferably, the inorganic salt is selected from the group consisting of sodium chloride, sodium sulfate, anhydrous aluminum sulfate, and mixtures of two or more thereof; more preferably, the inorganic salt is sodium chloride.

[0104] In (a), it is preferred that the at least two quinacridone pigments and the inorganic salt are substantially insoluble in the organic liquid, and preferably the solubility of the at least two quinacridone pigments and the inorganic salt in the organic liquid is in the range of 0 to 10 g / L, preferably 0.0001 to 9.5 g / L, more preferably 0.0005 to 9 g / L at a temperature in the range of 20 to 25° C. The solubility of the at least two quinacridone pigments is measured by methods known to those skilled in the art.

[0105] The particle size distribution of Dv(50) is preferably determined according to Reference Example 5.

[0106] The milled at least two quinacridone pigments preferably have a particle size distribution, determined according to Reference Example 5, of Dv(50) in the range of 20 to 140 nm, preferably 25 to 130 nm, more preferably 30 to 120 nm.

[0107] The mixed crystal quinacridone pigment composition preferably has a particle size distribution with Dv(50)<150 nm, and preferably the mixed crystal quinacridone pigment composition has a particle size distribution with Dv(50) determined according to Reference Example 5 in the range of 10 to 145 nm, more preferably 20 to 140 nm, more preferably 25 to 130 nm, more preferably 30 to 120 nm.

[0108] It is preferred that (a) further comprises milling the crude quinacridone pigment in the presence of a diketopyrrolopyrrole selected from the group consisting of PR264, PR272, and mixtures thereof.

[0109] The organic liquid is preferably selected from the group consisting of diethylene glycol, glycerin, diacetone alcohol, and mixtures of two or more thereof, preferably the organic liquid is diethylene glycol.

[0110] Preferably, the (a)(iii) synergist is a quinacridone derivative selected from the group consisting of quinacridone sulfonic acids and their salts, phthalimidoalkyl-quinacridones, imidazolylalkyl-quinacridones, pyrazolylalkyl-quinacridones, sulfonic acids and their salts of pyrazolylalkyl-quinacridones, dialkylaminoalkylsulfonamide derivatives of quinacridone, and mixtures of two or more thereof.

[0111] When the synergist of (a)(iii) is a quinacridone derivative, the quinacridone derivative may be selected from the group consisting of sulfonic acid derivatives and / or salts of quinacridone, quino[2,3-b]acridine-2-sulfonic acid, 5,7,12,14-tetrahydro-7,14-dioxo- and metal salts thereof, 5,12-dihydroquino[2,3-b]acridine-7,14-dione and formaldehyde reaction products with 3,5-dimethyl-1H-pyrazole, 5,12-dihydroquino[2, 3-b]acridine-7,14-dione and formaldehyde reaction products with 3,5-dimethyl-1H-pyrazole, sulfonated or 2-[(1,3-dihydro-1,3-dioxo-2H-isoindol-2-yl)methyl]-5,12-dihydroquino[2,3-b]acridine-7,14-dione, and mixtures of two or more thereof, preferably the quinacridone derivative is a monosulfonate metal salt derivative of PV19.

[0112] It is further preferred that the synergist in (a)(iii) is selected from the group consisting of natural or synthetic resins including esters and salts of abietic acid, hydrogenated or partially hydrogenated or dimerized rosins, non-ionic surfactants of the polysorbate type including esters or mixtures of esters formed from fatty acids, preferably lauric acid or sebacic acid, polyols, preferably sorbitan monolaurate and dibutyl sebacate, and mixtures of two or more thereof.

[0113] The (a)(iii) synergist is preferably present in an amount of from 1 to 10% by weight relative to the at least two quinacridone pigments of (a), preferably in an amount of from 1 to 5% by weight relative to the at least two quinacridone pigments of (a).

[0114] The synergist of (a)(iii) is preferably present in the range of 0.001 to 0.1 parts by weight based on the at least two quinacridone pigments of (a).

[0115] The mixed crystal quinacridone pigment composition containing at least two quinacridone pigments preferably has a particle size distribution, determined according to Reference Example 5, of Dv(50) in the range of 10 to 145 nm, preferably 20 to 140 nm, more preferably 25 to 130 nm, more preferably 30 to 120 nm.

[0116] The mixed crystal quinacridone pigment composition is preferably characterized by powder X-ray diffraction signals at diffraction angles 2θ of 5.9°±0.2° and 11.9°±0.2°.

[0117] The mixed crystal quinacridone pigment composition is preferably further characterized by powder X-ray diffraction signals at diffraction angles 2θ of 8.0°±0.2° and 17.9°±0.2° after addition of PR264.

[0118] The mixed crystal quinacridone pigment composition is preferably further characterized by powder X-ray diffraction signals at diffraction angles 2θ of 7.7°±0.2° and 15.7°±0.2° after addition of PR272.

[0119] Preferably, the method comprises a one-step solvent-salt-kneading process.

[0120] The present invention also relates to a mixed crystal quinacridone pigment composition obtainable or obtained according to the process of any one of the particular and preferred embodiments of the present invention for the preparation of the mixed crystal quinacridone pigment composition.

[0121] The mixed crystal quinacridone pigment composition preferably has a ratio of the diffraction peak intensity at a diffraction angle 2θ of 5.9±0.2° to the diffraction peak intensity at a diffraction angle 2θ of 11.9±0.2° of 3 or more, and preferably has a ratio of the diffraction peak intensity at a diffraction angle 2θ of 5.9±0.2° to the diffraction peak intensity at a diffraction angle 2θ of 11.9±0.2° in the range of 3 to 20, more preferably 6 to 10, as measured by powder X-ray diffraction, and preferably the ratio of the diffraction peak intensities is measured according to Reference Example 4 described in this specification.

[0122] The amount of the synergist in the mixed crystal quinacridone pigment composition is preferably in the range of 0.1 to 10 parts by mass, more preferably 0.5 to 3 parts by mass or 1 to 5 parts by mass, based on 100 parts by mass of the mixed crystal quinacridone pigment composition.

[0123] The particle size distribution of Dv(50) of the mixed crystal quinacridone pigment composition is preferably in the range of 10 to 145 nm, preferably 20 to 140 nm, more preferably 25 to 130 nm, and more preferably 30 to 120 nm, as determined in accordance with Reference Example 5 described herein.

[0124] The mixed crystal quinacridone pigment composition is preferably chlorine-free.

[0125] The present invention also relates to a printing ink or coating or plastic composition comprising any one of the mixed crystal quinacridone pigment compositions of the present invention specific and preferred embodiments.The printing ink or coating composition of the present invention is preferably suitable for use as a printing ink, an automotive coating, an architectural coating or an industrial coating.The printing ink composition of the present invention is preferably suitable for use as a digital printing ink, an inkjet ink, an electrophotographic toner, a water-based ink, a UV-curable ink, a solvent-based ink or an oil-based ink.

[0126] The present invention also relates to a printed or coated article comprising the printing ink or coating composition of any one of the particular and preferred embodiments of the present invention. Preferably, the printed article is a plastic article.

[0127] The present invention also relates to a plastic article comprising the mixed crystal quinacridone pigment composition of any one of the specific and preferred embodiments of the present invention.

[0128] The present invention is further described by a series of embodiments and combinations of embodiments resulting from the indicated dependency and back reference. In particular, in each instance where the scope of the embodiment is mentioned, it is to be noted that in the context of a term such as "any one of the methods of embodiment 1 to 4", it means that all the embodiments within this scope are expressly disclosed to those skilled in the art, that is, the expression of this term is understood by those skilled in the art to be synonymous with "any one of the methods of embodiment 1, 2, 3 and 4". Furthermore, it is to be expressly noted that the following series of embodiments represents a suitably constructed part of the general description directed to the preferred aspects of the present invention, and thus properly supports the scope of the claims of the present invention, but does not represent it.

[0129] 1. A method for producing a mixed crystal quinacridone pigment composition comprising the steps of: (a) mixing at least two quinacridone pigments at a temperature in the range of 40 to 120° C. with one or more of the following: (i) an inorganic salt in an amount ranging from 3 to 12 parts by weight relative to the at least two quinacridone pigments; (ii) an organic liquid selected from the group consisting of ethylene glycol, diethylene glycol, diacetone alcohol, dimethylformamide, glycerin, triethylene glycol, dipropylene glycol, ethylene glycol monobutyl ether, methyl ethyl ketone, cyclohexanone, dimethylacetamide, N-methylpyrrolidone, butyl acetate, glycerol triacetate, sulfolane, xylene, tetrahydrofuran, dimethyl sulfoxide, and mixtures of two or more thereof; and (iii) 0 to 10% by mass of a synergist based on the mixed crystal quinacridone pigment composition grinding in the presence of (b) discharging the at least two milled quinacridone pigments from step (a) into water; and (c) isolating the at least two milled quinacridone pigments from step (b). Including, The method wherein the milled at least two quinacridone pigments have a particle size distribution with a Dv(50) in the range of 10 to 145 nm.

[0130] 2. The method of embodiment 1, wherein the mixed crystal quinacridone pigment composition comprises PV19 and PR122.

[0131] 3. The method of embodiment 1 or 2, wherein the at least two quinacridone pigments comprise PV19 and PR122.

[0132] 4. The method of embodiment 2 or 3, wherein PV19 and PR122 are present in a ratio of 60:40 to 85:15 or 60:40 to 75:25.

[0133] 5. The method of any one of embodiments 2 to 4, wherein PV19 is 5,12-dihydroquinolino[2,3-b]acridine-7,14-dione and / or PR122 is 2,9-dimethyl-5,12-dihydroquinolino[2,3-b]acridine-7,14-dione.

[0134] 6. The method of any one of embodiments 1 to 5, further comprising a diketopyrrolopyrrole selected from the group consisting of PR264, PR272 and mixtures thereof, preferably, PR264 is 3,6-bis-biphenyl-4-yl-2,5-dihydropyrrolo[3,4-c]pyrrole-1,4-dione and PR272 is 3,6-bis(4-methylphenyl)-2,5-dihydropyrrolo[3,4-c]pyrrole-1,4-dione.

[0135] 7. The method of embodiment 6, wherein the amount of diketopyrrolopyrrole ranges from 0.1 to 15% by weight, preferably 1 to 15% by weight, more preferably 5 to 10% by weight, of the mixed crystal quinacridone pigment composition.

[0136] 8. The method of any one of the preceding embodiments, wherein in (a), the at least two quinacridone pigments comprise at least two crude quinacridone pigments, the at least two crude pigments comprise at least two quinacridone pigments obtained from a synthesis of at least two quinacridone pigments, preferably obtained from a synthesis without a finishing step, and the finishing step preferably comprises a modification selected from the group consisting of a particle size modification and a surface modification.

[0137] 9. The process of any one of the preceding embodiments, wherein in (a), the temperature is in the range of 60 to 90°C, preferably 40 to 90°C, more preferably 80 to 90°C, or the temperature is in the range of 45 to 100°C, preferably 50 to 90°C.

[0138] 10. The method of any one of the preceding embodiments, wherein in (a)(i), the inorganic salt is selected from the group consisting of alkali metal halides, alkali metal sulfates, alkaline earth metal halides, alkaline earth metal sulfates, and mixtures of two or more thereof; preferably, the inorganic salt is selected from the group consisting of sodium chloride, sodium sulfate, anhydrous aluminum sulfate, and mixtures of two or more thereof; more preferably, the inorganic salt is sodium chloride.

[0139] 11. The method of any one of embodiments 1 to 10, wherein in (a), the at least two quinacridone pigments and the inorganic salt are substantially insoluble in the organic liquid, and preferably the solubility of the at least two quinacridone pigments and the inorganic salt in the organic liquid is in the range of 0 to 10 g / L, preferably 0.0001 to 9.5 g / L, more preferably 0.0005 to 9 g / L at a temperature in the range of 20 to 25° C.

[0140] 12. The method of any one of the preceding embodiments, wherein the particle size distribution Dv(50) is determined according to Example 5.

[0141] 13. The method of any one of embodiments 1 to 12, wherein the milled at least two quinacridone pigments have a particle size distribution, determined according to Reference Example 5, of Dv(50) in the range of 20 to 140 nm, preferably 25 to 130 nm, more preferably 30 to 120 nm.

[0142] 14. The method of any one of embodiments 1 to 13, wherein the mixed crystal quinacridone pigment composition has a particle size distribution with Dv(50)<150 nm, preferably the mixed crystal quinacridone pigment composition has a particle size distribution with Dv(50) determined according to Reference Example 5 in the range of 10 to 145 nm, more preferably 20 to 140 nm, more preferably 25 to 130 nm, more preferably 30 to 120 nm.

[0143] 15. The method of any one of the preceding embodiments, wherein (a) further comprises milling the crude quinacridone pigment in the presence of a diketopyrrolopyrrole selected from the group consisting of PR264, PR272, and mixtures thereof.

[0144] 16. The method of any one of the preceding embodiments, wherein the organic liquid is selected from the group consisting of diethylene glycol, glycerin, diacetone alcohol, and mixtures of two or more thereof, preferably, the organic liquid is diethylene glycol.

[0145] 17. The method of any one of the preceding embodiments, wherein the synergist of (a)(iii) is a quinacridone derivative selected from the group consisting of quinacridone sulfonic acids and their salts, phthalimidoalkyl-quinacridones, imidazolylalkyl-quinacridones, pyrazolylalkyl-quinacridones, sulfonic acids and their salts of pyrazolylalkyl-quinacridones, dialkylaminoalkylsulfonamide derivatives of quinacridones, and mixtures of two or more thereof.

[0146] 18. Quinacridone derivatives include sulfonic acid derivatives and / or salts of quinacridone, quino[2,3-b]acridine-2-sulfonic acid, 5,7,12,14-tetrahydro-7,14-dioxo- and its metal salts, reaction products of 5,12-dihydroquino[2,3-b]acridine-7,14-dione and 3,5-dimethyl-1H-pyrazole with formaldehyde, 5,12-dihydroquino[2,3-b]acridine-7,14-dione and 3,5 18. The method of any one of the preceding embodiments, wherein the quinacridone derivative is selected from the group consisting of formaldehyde reaction products with 1,3-dimethyl-1H-pyrazole, sulfonated or 2-[(1,3-dihydro-1,3-dioxo-2H-isoindol-2-yl)methyl]-5,12-dihydroquino[2,3-b]acridine-7,14-dione, and mixtures of two or more thereof, preferably the quinacridone derivative is a monosulfonate metal salt derivative of PV19.

[0147] 19. The method of any one of the preceding embodiments, wherein the synergist in (a)(iii) is selected from the group consisting of natural or synthetic resins including esters and salts of abietic acid, hydrogenated or partially hydrogenated or dimerized rosins, nonionic surfactants of the polysorbate type including esters or mixtures of esters formed from fatty acids, preferably lauric acid or sebacic acid, polyols, preferably sorbitan monolaurate and dibutyl sebacate, and mixtures of two or more thereof.

[0148] 20. The method of any one of the preceding embodiments, wherein the synergist of (a)(iii) is present in an amount of 1 to 10% by weight relative to the at least two quinacridone pigments of (a), preferably in an amount of 1 to 5% by weight relative to the at least two quinacridone pigments of (a).

[0149] 21. The method of any one of the preceding embodiments, wherein the synergist of (a)(iii) is present in the range of 0.001 to 0.1 parts by weight relative to the at least two quinacridone pigments of (a).

[0150] 22. The method of any one of embodiments 1 to 21, wherein the mixed crystal quinacridone pigment composition comprising at least two quinacridone pigments has a particle size distribution, determined according to Reference Example 5, of Dv(50) in the range of 10 to 145 nm, preferably 20 to 140 nm, more preferably 25 to 130 nm, more preferably 30 to 120 nm.

[0151] 23. The method of any one of the preceding embodiments, wherein the mixed crystal quinacridone pigment composition is characterized by powder X-ray diffraction signals at diffraction angles 2θ of 5.9°±0.2° and 11.9°±0.2°.

[0152] 24. The method of embodiment 23, wherein the mixed crystal quinacridone pigment composition is further characterized by powder X-ray diffraction signals at diffraction angles 2θ of 8.0°±0.2° and 17.9°±0.2° after addition of PR264.

[0153] 25. The method of embodiment 23, wherein the mixed crystal quinacridone pigment composition is further characterized by powder X-ray diffraction signals at diffraction angles 2θ of 7.7°±0.2° and 15.7°±0.2° after addition of PR272.

[0154] 26. The method of any one of the preceding embodiments, wherein the method comprises a one-step solvent-salt-kneading process.

[0155] 27. A mixed crystal quinacridone pigment composition obtainable or obtained by the process of any one of embodiments 1 to 26.

[0156] 28. The mixed crystal quinacridone pigment composition of embodiment 27, wherein the ratio of the diffraction peak intensity at a diffraction angle 2θ of 5.9±0.2° to the diffraction peak intensity at a diffraction angle 2θ of 11.9±0.2° is 3 or more, and preferably the ratio of the diffraction peak intensity at a diffraction angle 2θ of 5.9±0.2° to the diffraction peak intensity at a diffraction angle 2θ of 11.9±0.2° is in the range of 3 to 20, more preferably 6 to 10, as measured by powder X-ray diffraction, and preferably the ratio of the diffraction peak intensities is measured according to Reference Example 4.

[0157] 29. The mixed crystal quinacridone pigment composition of embodiment 27 or 28, wherein the amount of synergist is in the range of 0.1 to 10 parts by weight, preferably 0.5 to 3 parts by weight or 1 to 5 parts by weight, per 100 parts by weight of the mixed crystal quinacridone pigment composition.

[0158] 30. The mixed crystal quinacridone pigment composition of any one of embodiments 27 to 29, wherein the particle size distribution, Dv(50), determined according to Reference Example 5, is in the range of 10 to 145 nm, preferably 20 to 140 nm, more preferably 25 to 130 nm, more preferably 30 to 120 nm.

[0159] 31. The mixed crystal quinacridone pigment composition of any one of embodiments 27 to 30, which is chlorine-free.

[0160] 32. A printing ink or coating or plastic composition comprising the mixed crystal quinacridone pigment composition of any one of embodiments 27 to 31.

[0161] 33. The printing ink or coating composition of embodiment 32, wherein the composition is suitable for use as a printing ink, automotive coating, architectural coating, or industrial coating.

[0162] 34. The printing ink composition according to embodiment 32, wherein the composition is suitable for use as a digital printing ink, an inkjet ink, an electrophotographic toner, a water-based ink, a UV-curable ink, a solvent-based ink or an oil-based ink.

[0163] 35. A printed or coated article comprising the printing ink or coating composition of any one of embodiments 32 to 34.

[0164] 36. The printed article of embodiment 35, wherein the article is a plastic article.

[0165] 37. A plastic article comprising the mixed crystal quinacridone pigment composition of any one of embodiments 27 to 31.

[0166] Although the present invention has been described in detail, including preferred embodiments thereof, it will be understood that those skilled in the art, upon consideration of this disclosure, may make modifications and / or improvements thereto which are within the scope and spirit of the present invention. EXAMPLES

[0167] The present invention is further described by the following non-limiting examples which further illustrate the invention but are not intended, and should not be construed, as limiting the scope of the invention.

[0168] Example 1 20.0 g of crude γ-PV19 and 11.1 g of PR122 were charged into a kneading apparatus (two-blade kneader) with a capacity of 0.6 liters. 214.3 g of sodium chloride and 45.0 g of diethylene glycol (DEG) were added to the kneader. The walls of the apparatus were thermostated at 80°C. After 12 hours of kneading, 3.6 g of PR264 and 1.1 g of monosulfonic acid metal salt derivative of PV19 were added and kneading was continued for 12 hours with the walls thermostated at 80°C. Kneading was then stopped and 1.6 L of water was added to the kneaded mass and stirred for 3 hours. The mixture was filtered and the pigment was washed with water until the conductivity of the filtrate was lower than 100 μS / cm. The wet press cake was dried in an oven at 80°C for 24 hours. The yield of the pigment obtained was 34.1 g, containing 56% PV19 and 31% PR122 in mixed crystals as a physical mixture, 10% PR264 and 3% monosulfonic acid metal salt derivatives of PV19. The pigment was ground in a mill to obtain a magenta powder.

[0169] Example 2 21.7 g of crude γ-PV19 and 9.3 g of PR122 were charged into a kneading apparatus (two-blade kneader) with a capacity of 0.6 liters. 214.3 g of sodium chloride and 45.0 g of diethylene glycol (DEG) were added to the kneader. The walls of the apparatus were thermostated at 80°C. After 12 hours of kneading, 3.6 g of PR272 and 1.1 g of monosulfonic acid metal salt derivative of PV19 were added and kneading was continued for 12 hours with the walls thermostated at 80°C. Kneading was then stopped and 1.6 L of water was added to the kneaded mass and stirred for 3 hours. The mixture was filtered and the pigment was washed with water until the conductivity of the filtrate was lower than 100 μS / cm. The wet press cake was dried in an oven at 80°C for 24 hours. The yield of the pigment obtained was 34.5 g, containing 61% PV19 and 26% PR122 in mixed crystals as a physical mixture, 10% PR272 and 3% monosulfonic acid metal salt derivatives of PV19. The pigment was ground in a mill to obtain a magenta powder.

[0170] Example 3 24.5 g of crude γ-PV19 and 8.2 g of PR122 were charged into a kneading apparatus (two-blade kneader) with a capacity of 0.6 liters. 214.3 g of sodium chloride and 45.0 g of diethylene glycol (DEG) were added to the kneader. The walls of the apparatus were thermostated at 80°C. After 6 hours of kneading, 1.8 g of PR272 and 1.1 g of monosulfonic acid metal salt derivative of PV19 were added and kneading was continued for 6 hours with the walls thermostated at 80°C. Kneading was then stopped and 1.6 L of water was added to the kneaded mass and stirred for 3 hours. The mixture was filtered and the pigment was washed with water until the conductivity of the filtrate was lower than 100 μS / cm. The wet press cake was dried in an oven at 80°C for 24 hours. The yield of the pigment obtained was 34.5 g and contained 69% PV19 and 23% PR122 in mixed crystals as a physical mixture, 5% PR272 and 3% monosulfonic acid metal salt derivatives of PV19. The pigment was ground in a mill to obtain a magenta powder.

[0171] Example 4 A kneading apparatus (two-blade kneader) of 0.6 liter capacity was charged with 20.7 g of crude γ-PV19 and 11.4 g of PR122. 214.3 g of sodium chloride and 45.0 g of diethylene glycol (DEG) were added to the kneader. The walls of the apparatus were thermostated at 80°C. After 12 hours of kneading, 3.6 g of PR272 were added and kneading was continued for 12 hours with the walls thermostated at 75-80°C. Kneading was then stopped and 1.6 L of water was added to the kneaded mass and stirred for 3 hours. The mixture was filtered and the pigment was washed with water until the conductivity of the filtrate was lower than 100 μS / cm. The wet press cake was dried in an oven at 80°C for 24 hours. The yield of the pigment obtained was 34.5 g, containing 58% PV19 and 32% PR122 in the mixed crystals as a physical mixture and 10% PR272. The pigment was ground in a mill to give a magenta powder.

[0172] Example 5 A kneading apparatus (two-blade kneader) of 0.6 liter capacity was charged with 20.7 g of crude γ-PV19 and 11.4 g of PR122. 214.3 g of sodium chloride and 45.0 g of diethylene glycol (DEG) were added to the kneader. The walls of the apparatus were thermostated at 76-80°C. After 12 hours of kneading, 3.6 g of PR264 were added and kneading was continued for 12 hours with the walls thermostated at 76°C. Kneading was then stopped and 1.6 L of water was added to the kneaded mass and stirred for 3 hours. The mixture was filtered and the pigment was washed with water until the conductivity of the filtrate was lower than 100 μS / cm. The wet press cake was dried in an oven at 80°C for 24 hours. The yield of the pigment obtained was 34.9 g and contained 58% PV19 and 32% PR122 in the mixed crystals as a physical mixture and 10% PR264. The pigment was ground in a mill to give a magenta powder.

[0173] Example 6 25.1 g of crude γ-PV19 and 8.4 g of PR122 were charged into a kneading apparatus (two-blade kneader) with a capacity of 0.6 liters. 214.3 g of sodium chloride and 45.0 g of diethylene glycol (DEG) were added to the kneader. The walls of the apparatus were thermostated at 80°C. After 6 hours of kneading, 1.8 g of PR264 and 0.4 g of monosulfonic acid metal salt derivative of PV19 were added and kneading was continued for 6 hours with the walls thermostated at 80°C. Kneading was then stopped and 1.6 L of water was added to the kneaded mass and stirred for 3 hours. The mixture was filtered and the pigment was washed with water until the conductivity of the filtrate was lower than 100 μS / cm. The wet press cake was dried in an oven at 80°C for 24 hours. The yield of the pigment obtained was 34.9 g and contained 70% PV19 and 24% PR122 in mixed crystals as a physical mixture, 5% PR272 and 1% monosulfonic acid metal salt derivatives of PV19. The pigment was ground in a mill to obtain a magenta powder.

[0174] Example 7 A kneading apparatus (two-blade kneader) of 0.6 liter capacity was charged with 18.8 g of crude γ-PV19 and 12.9 g of PR122. 214.3 g of sodium chloride and 45.0 g of diethylene glycol (DEG) were added to the kneader. The walls of the apparatus were thermostated at 75°C. After 12 hours of kneading, 3.6 g of PR272 and 0.4 g of monosulfonic acid metal salt derivative of PV19 were added and kneading was continued for 12 hours with the walls thermostated at 75°C. Kneading was then stopped and 1.6 L of water and 45 mL of 20% hydrochloric acid (aq) were added to the kneaded mass and stirred at 70°C for 2 hours. The mixture was filtered and the pigment was washed with water until the conductivity of the filtrate was lower than 100 μS / cm and the pH was higher than 6. The wet presscake was dried in an oven at 80°C for 24 hours. The yield of the pigment obtained was 34.6 g, containing 53% PV19 and 36% PR122 in mixed crystals as a physical mixture, 10% PR272 and 1% monosulfonic acid metal salt derivatives of PV19. The pigment was ground in a mill to obtain a magenta powder.

[0175] Example 8 20.2 g of crude γ-PV19 and 10.9 g of PR122 were charged into a kneading apparatus (two-blade kneader) of 0.6 liter capacity. 214.3 g of sodium chloride and 45.0 g of diethylene glycol (DEG) were added to the kneader. The walls of the apparatus were thermostated at 80°C. After 12 hours of kneading, 3.6 g of PR272 and 1.1 g of monosulfonic acid metal salt derivative of PV19 were added and kneading was continued for 12 hours with the walls thermostated at 78°C. Kneading was then stopped and 1.6 L of water was added to the kneaded mass and stirred for 3 hours. The mixture was filtered and the pigment was washed with water until the conductivity of the filtrate was lower than 100 μS / cm. The wet presscake was dried in an oven at 80°C for 24 hours. The yield of the pigment obtained was 34.5 g and contained 57% PV19 and 30% PR122 in mixed crystals as a physical mixture, 10% PR272 and 3% monosulfonic acid metal salt derivatives of PV19. The pigment was ground in a mill to obtain a magenta powder.

[0176] Example 9 367.5 g of crude γ-PV19 and 157.5 g of PR122 were charged into a kneading apparatus (two-blade kneader) with a capacity of 10 liters. 3300 g of sodium chloride and 650 g of diethylene glycol (DEG) were added to the kneader. The walls of the apparatus were thermostated at 50° C. After 6 hours of kneading, 22.1 g of PR264 and 5.5 g of monosulfonic acid metal salt derivative of PV19 were added and kneading was continued for 4 hours with the walls thermostated at 50° C. to ensure an internal temperature of 70° C. Then kneading was stopped and 5 L of water were added to the kneaded mass. The mixture was stirred for 3 hours at room temperature. Then 7 L of water and 140 g of 20% HCl (aq) were added and stirring was continued for 2 hours at 80° C. The mixture was filtered and the pigment was washed with water until the conductivity of the filtrate was lower than 100 μS / cm. The wet press cake was dried in an oven at 80° C. for 20 hours. The yield of the resulting pigment was 500 g, containing 67% PV19 and 28% PR122 in mixed crystals as a physical mixture, 4% PR264 and 1% monosulfonic acid metal salt derivatives of PV19. The pigment was ground in a mill to obtain a magenta powder.

[0177] Comparative Example 1 A kneading apparatus (two-blade kneader) of 0.6 liter capacity was charged with 26.8 g of crude γ-PV19 and 8.9 g of PR122. 214.3 g of sodium chloride and 45.0 g of diethylene glycol (DEG) were added to the kneader. The walls of the apparatus were thermostated at 80° C. and the mixture was kneaded for 12 hours. Then 1.6 g of water was added and the mixture was stirred for 3 hours and then filtered. The pigment was washed with water until the conductivity of the filtrate was lower than 100 μS / cm. The wet press cake was dried in an oven at 80° C. for 24 hours. The yield of the pigment obtained was 35.0 g and contained 75% PV19 and 25% PR122 in the mixed crystals. The pigment was ground in a mill to obtain a magenta powder.

[0178] Comparative Example 2 25.9 g of crude γ-PV19 and 8.7 g of PR122 were charged into a kneading apparatus (two-blade kneader) with a capacity of 0.6 liters. 214.3 g of sodium chloride and 45.0 g of diethylene glycol (DEG) were added to the kneader. The walls of the apparatus were thermostated at 80-83°C and the mixture was kneaded for 6 hours. Then, 1.1 g of monosulfonic acid metal salt derivative of PV19 was added and kneading was continued for 6 hours with the walls thermostated at 83°C. Then, 1.6 L of water was added and the mixture was stirred for 3 hours and then filtered. The pigment was washed with water until the conductivity of the filtrate was lower than 100 μS / cm. The wet press cake was dried in an oven at 80°C for 24 hours. The yield of the pigment obtained was 33.2 g, containing 73% PV19 and 24% PR122 in the mixed crystals as a physical mixture and 3% monosulfonic acid metal salt derivative of PV19. The pigment was ground in a mill to give a magenta powder.

[0179] Test Method Color characteristics: Preparation of 5% by weight pigment millbase (Preparation 1) A 5% by weight pigment millbase was prepared by combining 5% by weight pigment with 95% by weight of a heated alkyd-based solvent-based binder test system in a sealable container. A dispersing medium (e.g., glass beads 3 mm diameter) was added to the container in a mass ratio of 1:1.5 millbase components:beads, and the container was placed in a Skandex disperser to disperse the millbase components for 4 hours.

[0180] Preparation of 45% by weight pigment titanium dioxide millbase (Preparation 2) A 45% by weight white millbase was prepared by combining 45% by weight titanium dioxide pigment (e.g., Kronos 2310 supplied by Kronos International Inc.) and 55% by weight of a heated alkyd-based solvent-based binder test system in a sealable container. A dispersing medium (e.g., glass beads 3 mm diameter) was added to the container in a mass ratio of 1:1.5 millbase components:beads, and the container was placed in a Skandex disperser to disperse the millbase components for 1 hour.

[0181] Preparation of white reduced product (Preparation 3) 50% by weight of the 5% by weight pigment mill base (preparation 1) and 50% by weight of the 45% by weight pigment titanium dioxide mill base (preparation 2) are mixed together in a speed mixer (e.g., Hauschild series DAC800FVZ) for 2000 min. -1 The mixture was mixed at rt for 60 seconds to provide a 10:90 pigment:titanium oxide white reduced product.

[0182] Masstone Panel Preparation (Preparation 4) 5% by weight of the pigment millbase (Preparation 1) was manually drawn onto a black and white contrast board (e.g. Leneta 2A-3) using a 150 μm spiral applicator. The coating was left to dry at room temperature for 20 minutes and then baked at 130° C. for 30 minutes.

[0183] Preparation of white reduction panel (Preparation 5) The white reduction (Preparation 3) was manually drawn onto a black and white contrast board (e.g. Leneta 2A-3) using a 150 μm spiral applicator. The coating was left to dry at room temperature for 20 minutes and then baked at 130° C. for 30 minutes.

[0184] Transparency (ddE) Evaluation (Reference Example 1) Colorimetric evaluation was performed according to spectroscopy (ISO18314-1(2015)) in d / 8° or 8° / d geometry with the specular component removed. Masstone panels (prepared according to preparation 4) were used to determine transparency using the colorimetric parameter scattering-dE according to DIN55988. The difference between any transparency of Examples 1-8 or Comparative Examples 1 and 2 and the reference material Cinquasia Magenta D4570 was obtained as ddE. Cinquasia Magenta D4570 was set as a reference because its hue is close to the target hue of the invention discussed and helps to judge the performance of the invention compared to the state-of-the-art PV19 / PR122 mixed crystal (Comparative Example).

[0185] Hue (dH) Evaluation (Reference Example 2) The term H (hue) used herein means the hue in the L*C*H color space (also called CIELAB) defined by the Commission Internationale de L'Eclairage. dH represents the difference in hue between two samples. Cinquasia Magenta D4570 was set as the reference because its hue is close to the target hue of the discussed invention and helps to judge the performance of the invention compared to the state-of-the-art PV19 / PR122 mixed crystal (comparative example).

[0186] Colorimetric evaluation was performed using a white reduction panel (prepared according to preparation 5) in a geometry of d / 8° or 8° / d, including the specular component and excluding the 4% specular component calculated afterwards, according to the spectroscopic method (ISO 18314-1 (2015)). Hue was determined after matching the shadow depth for illuminant D65 and a 10° standard observer, according to ISO 11664-4 (2008).

[0187] Evaluation of relative color strength (CS) (Reference Example 3) The color strength CS was measured by iteratively matching the color depth to 1 / 3 shade depth according to ISO18314-2 (2015) using a white reduction panel (preparation 5). The relative color strength was evaluated against Cinquasia Magenta D4570 because its hue is close to the target hue of the discussed invention and helps judge the performance of the invention compared to the state-of-the-art PV19 / PR122 mixed crystal (comparative example).

[0188] The evaluation criteria were as follows: ○ = Meets the criteria × = Criteria not met.

[0189] Transparency: The more negative the value, the more transparent: ○:ddE<-3.0 ×:ddE>-3.0.

[0190] Color Intensity: The higher the value, the greater the relative color intensity. ○:CS≧75 ×:CS<75.

[0191] Hue: The more positive the dH value, the more yellow or better the shading. ○:dH≧-3 ×:dH<-3.

[0192] Measurement method of PXRD (powder X-ray diffraction) and evaluation method of peak intensity ratio (Reference Example 4) PXRD was measured using a powder X-ray diffractometer (Rigaku MiniFlex600 or Bruker D8 Advance Series2) with CuKα radiation as the X-ray source. The scanning range (2θ) was set to 4° to 35° 2θ.

[0193] The intensity ratio was defined as follows: Intensity ratio=(diffraction peak intensity when the diffraction angle 2θ is around 5.9°) / (diffraction peak intensity when the diffraction angle 2θ is around 11.9°).

[0194] Formation criteria for mixed crystals of PR19 and PR122: ○: Strength ratio>3 ×: Intensity ratio <3.

[0195] Measurement method of particle size distribution (Dv) (Reference Example 5) To prepare the dispersion, 25 g of pigment was added to a 400 ml glass bottle containing 75 g of a blend of deionized water (37.5 g), isopropanol (4.5 g), diethylene glycol monobutyl ether (3.0 g) and a high molecular weight block copolymer dispersion (Disperbyk-190 from BYK-Chemie GmbH, 30.0 g). The dispersion to pigment ratio was 0.48 (dry basis). The pigment was predispersed by mixing the resulting mixture at 5000 rpm for 5 minutes using a high speed disperser (Dispermat LC-230) equipped with a 30 mm sawtooth blade. Then, 200 g of zirconia beads (0.7-0.9 mm diameter) were added to the glass jar and the pigment was dispersed for 4 hours using a Disperser DAS200 device (Lau GmbH).

[0196] The resulting pigment dispersion was allowed to stand for 24 hours and then analyzed for particle size distribution by dynamic light scattering (Malvern Zetasizer, Malvern Instruments Ltd).

[0197] Test results

[0198] [Table 1]

[0199] As shown in Table 1, Examples 1 to 8 of the present invention met all the requirements in terms of transparency, color intensity, and hue (◯), and showed excellent color characteristics. In contrast, Comparative Examples 1 and 2 did not meet the target characteristics in at least one example each in terms of transparency, color intensity, and hue (×).

[0200] [Table 2]

[0201] As shown in Table 2, Examples 1 to 8 of the present invention exhibited X-ray diffraction signals characteristic of mixed crystals of PV19 and PR122. Furthermore, Table 2 confirms that PR264 and PR272 are not incorporated into the mixed crystals but are present in the physical mixture due to the occurrence of X-ray diffraction signals characteristic of the crystal lattices of the individual PR264 or PR272 components.

[0202] [Table 3]

[0203] As shown in Table 3, inventive Example 9 exhibited a particle size distribution with Dv(50)<150 nm. This is in contrast to the reference sample Cinquasia Magenta D4570, which exhibits a Dv(50)>150 nm. The narrow particle size distribution of inventive Example 9 is demonstrated by the Dv(10), Dv(50) and Dv(90) values ​​compared to those obtained for the reference sample Cinquasia Magenta D4570.

[0204] References - JP2019112534 - EP3786236A1 - EP3778784 - EP3533842 - US7166158 - EP3480264B1 - High Performance Pigments, edited by Hugh M. Smith, page 296, Wiley-VCH Verlag-GmbH, 2002, ISBN3-527-30204-2

Claims

1. A method for producing a mixed crystal quinacridone pigment composition comprising a one-step solvent-salt-kneading process comprising the steps of: (a) subjecting a crude quinacridone pigment to a temperature in the range of about 40-120° C., or 60-90° C., or 40-90° C., or 80-90° C., as follows: (i) an inorganic salt in the range of about 3 to about 12 parts by weight based on the crude quinacridone pigment; (ii) an organic liquid in which the crude quinacridone pigment and the salt are substantially insoluble; and (iii) optionally, a quinacridone synergist; grinding in the presence of (b) discharging the crude quinacridone pigment from step (a) into water, thereby obtaining a water-pigment mixture; and (c) isolating a quinacridone pigment having a particle size distribution of Dv(50)<150 nm from the mixture. The method includes:

2. 2. The method of claim 1, wherein the composition comprises a combination of PV19 and PR122, preferably the composition is a combination of PV19 and PR122.

3. 3. The method of claim 2, further comprising a diketopyrrolopyrrole selected from the group consisting of PR264, PR272, or both, in the range of 0.1 to 15%, or 1 to 15%, or 5 to 10% by weight of the total composition.

4. 3. The method of claim 2, wherein the PV19 and PR122 are present in a ratio of 60:40 to 85:15 or 60:40 to 75:

25.

5. The method according to claim 1 or 2, wherein the mixed crystal quinacridone pigment composition has a particle size distribution with Dv(50)<150 nm, preferably the mixed crystal quinacridone pigment composition has a particle size distribution with Dv(50) determined according to Reference Example 5 in the range of 10 to 145 nm, more preferably 20 to 140 nm, more preferably 25 to 130 nm, more preferably 30 to 120 nm.

6. 3. The method of claim 1 or 2, wherein (a) further comprises milling the crude quinacridone pigment in the presence of a diketopyrrolopyrrole selected from the group consisting of PR264, PR272, and mixtures thereof.

7. 3. The method of claim 1 or 2, wherein PV19 is 5,12-dihydroquinolino[2,3-b]acridine-7,14-dione, and / or PR122 is 2,9-dimethyl-5,12-dihydroquinolino[2,3-b]acridine-7,14-dione, and / or PR264 is 3,6-bis-biphenyl-4-yl-2,5-dihydropyrrolo[3,4-c]pyrrole-1,4-dione, and / or PR272 is 3,6-bis(4-methylphenyl)-2,5-dihydropyrrolo[3,4-c]pyrrole-1,4-dione.

8. The method according to claim 1 or 2, wherein the one-step solvent-salt-kneading process is a solvent-salt-kneading process.

9. 3. The method of claim 1 or 2, wherein in (a), the crude quinacridone pigment comprises the pigment obtained from a synthesis of the quinacridone pigment, preferably obtained from a synthesis without a finishing step, the finishing step preferably including a modification selected from the group consisting of a particle size modification and a surface modification.

10. 3. The method according to claim 1 or 2, wherein in (a), the temperature is in the range of 60 to 90°C, preferably 40 to 90°C, more preferably 80 to 90°C, or the temperature is in the range of 45 to 100°C, preferably 50 to 90°C.

11. 3. The method of claim 1 or 2, wherein in (a)(i), the inorganic salt is selected from the group consisting of alkali metal halides, alkali metal sulfates, alkaline earth metal halides, alkaline earth metal sulfates, and mixtures of two or more thereof, preferably, the inorganic salt is selected from the group consisting of sodium chloride, sodium sulfate, anhydrous aluminum sulfate, and mixtures of two or more thereof, more preferably, the inorganic salt is sodium chloride.

12. 3. The method of claim 1 or 2, wherein in (a)(ii), the solubility of the crude quinacridone pigment and the salt in the organic liquid is in the range of 0 to 10 g / L, preferably 0.0001 to 9.5 g / L, more preferably 0.0005 to 9 g / L at a temperature in the range of 20 to 25° C.

13. 3. The method of claim 1 or 2, wherein in (a)(ii), the salt comprises an inorganic salt.

14. 3. The method of claim 1 or 2, wherein the mixed crystal quinacridone pigment composition comprises a quinacridone synergist, and from 0 to 10 weight percent of the mixed crystal quinacridone pigment composition consists of the quinacridone synergist.

15. The method according to claim 1 or 2, wherein the particle size distribution Dv(50) is determined according to Example 5.

16. The method according to claim 1 or 2, wherein in (c), the quinacridone pigment has a particle size distribution, Dv(50), determined according to Reference Example 5, in the range of 10 to 145 nm, preferably 20 to 140 nm, more preferably 25 to 130 nm, more preferably 30 to 120 nm.

17. The method of claim 1 or 2, wherein in (a)(ii), the organic liquid comprises a solvent.

18. 3. The method of claim 1 or 2, comprising a solvent selected from the group consisting of ethylene glycol, diethylene glycol, diacetone alcohol, dimethylformamide, glycerin, triethylene glycol, dipropylene glycol, ethylene glycol monobutyl ether, methyl ethyl ketone, cyclohexanone, dimethylacetamide, N-methylpyrrolidone, butyl acetate, glycerol triacetate, sulfolane, xylene, tetrahydrofuran, butanol, water, dimethylsulfoxide, and blends thereof, preferably the solvent is selected from the group consisting of ethylene glycol, diethylene glycol, diacetone alcohol, dimethylformamide, glycerin, triethylene glycol, dipropylene glycol, ethylene glycol monobutyl ether, methyl ethyl ketone, cyclohexanone, dimethylacetamide, N-methylpyrrolidone, butyl acetate, glycerol triacetate, sulfolane, xylene, tetrahydrofuran, dimethylsulfoxide, and mixtures of two or more thereof.

19. 20. The method of claim 18, wherein the at least one solvent comprises one or more of diethylene glycol, diacetone alcohol, and glycerin, preferably the solvent is diethylene glycol.

20. 3. The method of claim 1 or 2, wherein the synergist is a quinacridone derivative selected from the group consisting of quinacridone sulfonic acids and their salts, phthalimidoalkyl-quinacridones, imidazolylalkyl-quinacridones, pyrazolylalkyl-quinacridones, pyrazolylalkyl-quinacridone sulfonic acids and their salts, and dialkylaminoalkylsulfonamide derivatives of quinacridone.

21. The synergist may be selected from the group consisting of sulfonic acid derivatives and / or salts of quinacridone, quino[2,3-b]acridine-2-sulfonic acid, 5,7,12,14-tetrahydro-7,14-dioxo- and metal salts thereof, formaldehyde reaction products with 5,12-dihydroquino[2,3-b]acridine-7,14-dione and 3,5-dimethyl-1H-pyrazole, formaldehyde reaction products with 5,12-dihydroquino[2,3-b]acridine-7,14-dione and 3,5-dimethyl-1H-pyrazole, sulfonated or 2-[(1,3-dihydro-1,3 3. The method of claim 1 or 2, wherein the surfactant is selected from the group consisting of: [-dioxo-2H-isoindol-2-yl)methyl]-5,12-dihydroquino[2,3-b]acridine-7,14-dione, natural or synthetic resins including esters and salts of abietic acid, hydrogenated or partially hydrogenated or dimerized rosins, non-ionic surfactants of the polysorbate type including esters or mixtures of esters formed from fatty acids, such as lauric acid or sebacic acid, polyols, such as sorbitan monolaurate or dibutyl sebacate, and blends thereof.

22. 3. The method of claim 1 or 2, wherein the synergist is present in an amount of 1 to 10% by weight based on the crude quinacridone pigment, preferably the synergist of (a)(iii) is present in an amount of 1 to 10% by weight based on the crude quinacridone pigment of (a).

23. 3. The method of claim 1 or 2, wherein the synergist is present in an amount of 1 to 5% by weight based on the crude quinacridone pigment, preferably the synergist of (a)(iii) is present in an amount of 1 to 5% by weight based on the crude quinacridone pigment of (a).

24. 3. The method of claim 1 or 2, wherein the synergist is present in the range of about 0.001 to about 0.1 parts by weight based on the crude quinacridone pigment, preferably the synergist of (a)(iii) is present in the range of about 0.001 to about 0.1 parts by weight based on the crude quinacridone pigment of (a).

25. 3. The method according to claim 1 or 2, wherein the narrow particle size distribution obtained by Dv(50) is <150 nm, preferably said narrow particle size distribution obtained by Dv(50) is in the range of 10 to 145 nm, more preferably 20 to 140 nm, more preferably 25 to 130 nm, more preferably 30 to 120 nm, as determined according to Reference Example 5.

26. 3. The method of claim 1 or 2, wherein the composition is characterized by a powder X-ray diffraction signal at diffraction angles 2θ of about 5.9°±0.2° and 11.9°±0.2°.

27. 27. The method of claim 26, wherein the composition is further characterized by a powder X-ray diffraction signal after addition of PR264 at diffraction angles of 8.0°±0.2° 2θ and 17.9°±0.2° 2θ.

28. 27. The method of claim 26, wherein the composition is further characterized by a powder X-ray diffraction signal after addition of PR272 at diffraction angles of 7.7°±0.2° 2θ and 15.7°±0.2° 2θ.

29. A mixed crystal quinacridone pigment composition resulting from the process of claim 1 or 2.

30. 30. The pigment composition according to claim 29, wherein a ratio of a diffraction peak intensity at a diffraction angle 2θ of 5.9±0.2° to a diffraction peak intensity at a diffraction angle 2θ of 11.9±0.2° is 3 or more, and preferably a ratio of a diffraction peak intensity at a diffraction angle 2θ of 5.9±0.2° to a diffraction peak intensity at a diffraction angle 2θ of 11.9±0.2° is in the range of 3 to 20, more preferably 6 to 10, as measured by powder X-ray diffraction, and preferably the ratio of the diffraction peak intensities is measured according to Reference Example 4.

31. The pigment composition according to claim 29, wherein the amount of the quinacridone pigment derivative contained is 0.1 to 10 parts by mass per 100 parts by mass of the pigment, and preferably the amount of the quinacridone pigment derivative contained in (a)(iii) is 0.1 to 10 parts by mass per 100 parts by mass of the mixed crystal quinacridone pigment composition.

32. The pigment composition according to claim 29, wherein the amount of the quinacridone pigment derivative contained is 1 to 5 parts by mass per 100 parts by mass of the pigment, and preferably the amount of the quinacridone pigment derivative contained in (a)(iii) is 1 to 5 parts by mass per 100 parts by mass of the mixed crystal quinacridone pigment composition.

33. The pigment composition according to claim 29, wherein the amount of the quinacridone pigment derivative contained is 0.5 to 3 parts by weight, preferably 1 to 3 parts by weight, per 100 parts by weight of the pigment, and preferably the amount of the quinacridone pigment derivative contained in (a)(iii) is 0.5 to 3 parts by weight, preferably 1 to 3 parts by weight, per 100 parts by weight of the mixed crystal quinacridone pigment composition.

34. 30. The pigment composition according to claim 29, wherein the narrow particle size distribution obtained at Dv(50) is <150 nm, preferably said narrow particle size distribution obtained at Dv(50) is in the range of 10 to 145 nm, more preferably 20 to 140 nm, more preferably 25 to 130 nm, more preferably 30 to 120 nm, determined according to Reference Example 5.

35. 30. The pigment composition of claim 29, wherein the composition is chlorine-free.

36. 30. A printing ink or coating or plastic composition comprising the pigment composition of claim 29.

37. 37. A printing ink or coating composition according to claim 36, wherein the composition is suitable for use as a printing ink, automotive coating, architectural coating or industrial coating.

38. 38. The printing ink composition of claim 37, wherein the composition is suitable for use as a digital printing ink, an inkjet ink, an electrophotographic toner, a water-based ink, a UV curable ink, a solvent-based ink or an oil-based ink.

39. 36. A printed or coated article comprising the printing ink or coating composition of claim 35.

40. 40. The printed article of claim 39, wherein the article is a plastic article.

41. 30. A plastic article comprising the pigment composition of claim 29.

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