PIGMENT FORMULATIONS BASED ON C.I. Pigment Violet

Abstract

A pigment formulation comprising: a) as base pigment C.I. Pigment Violet 23 of Formula (I); b) as pigment synergist a perylene tetracarboxylic diimide compound of general formula (II) containing at least one sulfonic acid group, wherein: A is divalent gt; nR1 or gt; an NR2-SO3-X + group; r1 is a hydrogen atom, or a C1-C30-alkyl group, preferably a C1-C18-alkyl group, in particular a C1-C4-alkyl group, or an aryl group, preferably a phenyl group, in which the aryl group is unsubstituted or mono-or polysubstituted by a halogen such as chlorine or bromine, a sulfo group, a C1-C4-alkyl group such as methyl or ethyl, a C1-C4-alkoxy group such as methoxy or ethyoxyl, or a phenylazo group; r2 is a linear or branched C1-C6-alkylene group, in particular an ethylidene group or a propylidene group; x < + > is NR3R4R5R6 < + >, and R3, R4, R5 and R6 are H, linear chain or branched chain C1-C30-alkyl, phenyl or phenyl-C1-C6-alkyl. # imgabs0 #

Description

Technical Field

[0001] The present invention relates to a pigment preparation based on CI Pigment Violet 23, a method for its preparation and use thereof. Background Art

[0002] In many cases, organic pigments produced after their synthesis or finishing are not suitable for direct use in printing inks or printing ink concentrates. In particular, in ester-rich systems, problems such as insufficient pigment wetting and flocculation often occur, so that optimal color strength, gloss and transparency as well as the required purity cannot be achieved.

[0003] During storage, viscosity tends to increase, making further processing difficult or impossible, especially in concentrated printing inks.

[0004] Inadequately dispersed and wetted pigments at low viscosities can also be disruptive in further processing, where they can lead to sedimentation problems in particular.

[0005] In order to improve the application properties of the pigments, it is therefore advantageous to add pigment synergists to the synthetic raw materials or pre-finished products to produce pigment preparations, which have a significantly improved quality compared to the corresponding base pigments.

[0006] Patent document EP 0 504 922 A1 discloses a pigment preparation containing the following ingredients:

[0007] a) CI Pigment Violet 23 of Formula I as base pigment;

[0008]

[0009] as well as

[0010] b) dioxazine compounds of the general formula Ia as pigment synergists,

[0011]

[0012] in:

[0013] Q is an n-valent group according to the basic structure of formula I;

[0014] X + H + 、M m+ / m equivalent m-valent metal cation or N+R1R 2 R 3 Ammonium ion with R+ structure.

[0015] Patent document EP 486 531 B1 describes sulfonic acid group-containing perylene compounds, especially N-methyl-N-ethane-2-sulfonic acid-perylenetetracarboxylic acid diimide, which can be used as fluorescent dyes, as colorants for dyeing high molecular weight organic materials, and generally as pigment dispersants for azo, quinacridone, and especially perylene compound-based pigments. Summary of the invention

[0016] The present invention aims to further develop pigment preparations based on CI Pigment Violet 23 (PV23). The goal here is to optimize the color properties, such as increasing color strength, gloss and transparency, while improving the rheological properties to nearly achieve Newtonian flow properties and perfect storage stability.

[0017] The solution of the present invention to achieve the above-mentioned object is a pigment preparation, comprising:

[0018] a) CI Pigment Violet 23 of Formula I as base pigment;

[0019]

[0020] b) perylenetetracarboxylic acid diimide compounds of the general formula II containing at least one sulfonic acid group as pigment synergist,

[0021]

[0022] in:

[0023] A is divalent>NR 1 or>NR 2 -SO 3 - X + Group;

[0024] R 1 A hydrogen atom or C 1 -C 30 -alkyl (preferably C 1 -C 18 -alkyl, especially C 1 -C 4 -alkyl) or aryl (preferably phenyl), wherein the aryl is unsubstituted or substituted with halogen (such as chlorine or bromine), sulfonyl, C 1 -C 4 -alkyl (such as methyl or ethyl), C 1 -C 4 - alkoxy (such as methoxy or ethoxy) or phenylazo mono- or polysubstituted, for example mesityl;

[0025] R 2 Straight or branched chain C 1 -C 6- alkylene, in particular ethylene or propylene;

[0026] X + NR 3 R 4 R 5 R 6+ ,in,

[0027] R 3 , R 4 , R 5 , R 6 H, straight chain or branched chain C 1 -C 30 -alkyl, phenyl or phenyl-C 1 -C 6 - alkyl, for example benzyl.

[0028] The pigment preparations of the invention are characterized by high color strength, high gloss, high transparency, very good rheological properties and very good compatibility with ester-rich mixed solvents.

[0029] Surprisingly, the sulfonic acid group-containing perylene tetracarboxylic acid diimide compounds of the general formula II are very suitable as pigment synergists for CI Pigment Violet 23 because of the huge structural difference between dioxazine compounds (such as PV23) and perylene compounds.

[0030] In preferred pigment preparations of formula II, R 1 is methyl, R 2 C 2 Particularly preferred is the ammonium salt of N-methyl-N-ethane-2-sulfonic acid-perylenetetracarboxylic acid diimide.

[0031] In a more preferred pigment preparation, R 3 is hexadecyl, R 4 , R 5 and R 6 It is methyl.

[0032] In a more preferred pigment preparation, R 3 and R 4 is hexadecyl and / or octadecyl, R 5 and R 6 It is methyl.

[0033] Preferably, the pigment synergist of general formula II is composed of the corresponding perylenetetracarboximide compound and an appropriate ammonium halide compound NR 3 R 4 R 5 R 6+ Hal - Generated in the pigment preparation itself, the perylenetetracarboximide compound contains at least one sulfonic acid group and has the general formula III,

[0034]

[0035] Among them, M + H + , metal cation or M m+ / m equivalent m-valent metal cation. The preferred halide is chloride.

[0036] Suitable metal cations M + or M m+ Li+, Na+, K+, Mg2+, Ca 2 +、Sr 2 +、Ba 2 +, Mn2+, Cu2+, Ni 2 +、Cd 2 +, Co2+, Zn2+, Fe2+, Al3+, Cr 3 + or Fe3, preferably Na+ and K+.

[0037] The pigment preparation claimed in the present invention can be prepared in various ways. According to the present invention, the synergist can be added to the base pigment during the preparation process in the form of an aqueous suspension of the components or a mixture thereof or a suspension containing an aqueous solvent, in the form of a wet pressed cake before drying or in the form of a dried powder, in particular

[0038] a) in the wet press cake of the base pigment;

[0039] b) In the fine dispersion of coarse crystalline pigment raw materials, for example:

[0040] b1) Dry grinding with or without added salt,

[0041] b2) Wet grinding with or without solvent;

[0042] c) before, during or after a subsequent solvent finishing treatment, in the treatment of already finely divided pigment raw materials;

[0043] d) in a mechanical mixing process in the dry state, for example mixing ground synergist with pigment powder; and finally

[0044] e) Pigments should only be added to the intended application medium.

[0045] According to the invention, dry grinding and wet grinding are preferred techniques for preparing the pigment preparations. The pigment synergist can be added, for example, during dry grinding of the pigment raw material on a roller mill or a vibrating mill (with or without additional grinding aids), or during wet grinding of the pigment raw material on a vibrating mill, a roller mill or a bead mill to the aqueous, organic or aqueous-organic grinding medium. The use of the synergist before, during or after the printing finishing of the bottom pigment in an aqueous or aqueous-organic medium has also proven to be reliable.

[0046] When preparing the pigment preparations according to the invention, the amount of pigment synergist (b) added to the base pigment (a) is not restricted to a specific maximum value, as long as the desired pigment quality is not negatively affected, but generally the content of the individual synergists is 0.1 to 30 wt.%, in particular 0.5 to 5 wt.%, based on the weight of the respective pigment.

[0047] The pigment preparations claimed in the present invention may contain further ingredients, for example surfactants, resins or dust suppressants, in addition to the pigment (a) and the pigment synergist (b).

[0048] Therefore, the pigment preparation in the context of the present invention is essentially composed of the following components:

[0049] a) 99.5 to 70 wt.% of a base pigment of formula I;

[0050] b) 0.5 to 30 wt.% of a pigment synergist of formula II;

[0051] c) 0 to 5 wt.% of a nonionic surfactant; and

[0052] d) 0-5 wt.% of common additives,

[0053] The proportion of each component is based on the total weight of the preparation (100%).

[0054] A pigment preparation based on CI Pigment Violet 23 with excellent color and rheological properties can be produced in a simple manner by firstly wet grinding the PV 23 raw pigment obtained after drying of the coarse-crystalline wet press cake obtained during the pigment synthesis in a liquid medium in a stirred ball mill in the presence of a pigment synergist until the desired fineness distribution of the pigment particles is achieved, and then directly (in the case of intermediate separation, after reabsorption into a liquid) subjecting the thus obtained millbase suspension to a standard finishing treatment at elevated temperature with the participation of an organic solvent, wherein the pigment synergist can be added at any time during the two treatment stages mentioned above. The measures taken in the claimed method for formulating the base pigment of the formula I combine fine distribution and finishing in a simple and elegant manner.

[0055] The groundbreaking preparation of such pigment preparations requires very high grinding efficiencies, which in turn must be achieved by using specially designed agitator ball mills and adhering to specified grinding and finishing conditions. Apparatus suitable for the required grinding efficiencies are agitator ball mills designed for discontinuous or continuous operation, with cylindrical or hollow cylindrical grinding chambers of horizontal or vertical design, specific power densities of more than 2.5 kW per litre of grinding chamber and agitator peripheral speeds of more than 12 metres per second. The energy released per unit time by the agitator is transferred to the ground material in the form of comminution work and friction energy as heat. In order to dissipate the large amounts of heat successfully, constructive precautions must be taken to reduce the ratio of grinding chamber to grinding chamber surface (cooling surface).

[0056] The grinding media used are microspheres of zirconium oxide, mixed zirconium oxide, aluminum oxide or quartz with a diameter not greater than 1 mm; microspheres with a diameter of 0.2 to 1 mm, preferably 0.3 to 0.5 mm, are suitable for use.

[0057] When finely dispersing with a continuous stirred ball mill, the grinding media is preferably separated from the ground material by centrifugal separation, so that the separation device practically does not come into contact with the grinding media and thus clogging is largely prevented. The stirred ball mill is operated with a high filling degree of the grinding media. In a continuous stirred ball mill, the grinding chamber is practically completely filled with grinding media.

[0058] The pigment concentration in the grinding material should not be greater than 40wt.%, generally 10-35wt.%, preferably 10-20wt.%. The grinding is carried out in an aqueous, aqueous / organic or organic solvent medium, and the pH value is preferably in the alkaline or neutral range. In addition to the liquid phase and the pigment raw material, the grinding material may also contain a pigment dispersant, a surfactant and other additives. Depending on the required fineness, the residence time of the grinding material in the stirred ball mill is generally 10-60 minutes, suitably 10-45 minutes, preferably 10-30 minutes. The grinding is carried out in a temperature range of 0-100°C, suitably at a temperature of 10-60°C, preferably 20-50°C.

[0059] The liquid grinding media used are: water; C 1 -C 4 Alkanols, such as methanol, ethanol, n-propanol, isopropanol, n-butanol, tert-butanol or isobutanol; cycloalkanols, such as cyclohexanol; C 1 -C 6Dialkyl ketones, such as acetone, diethyl ketone, methyl isobutyl ketone or methyl ethyl ketone; ethers and glycol ethers, such as methyl glycol, ethyl glycol, butyl glycol, ethyl diglycol or methoxybutanol; fatty acid amides, such as formamide or dimethylformamide; cyclic carboxylic acid amides, such as N-methylpyrrolidone, valerolactam and caprolactam; heterocyclic bases, such as pyridine, morpholine or picoline; and dimethyl sulfoxide or mixtures of these solvents with water; particularly preferred are aqueous isobutanol solutions, such as 5% isobutanol.

[0060] The pigment synergist can be added once or in two or more portions; it can be added before, during or after grinding and before, during or after finishing. The most suitable time for addition must be determined in advance by exploratory tests. The addition can be done in the dry state, in the form of a wet press cake or as an aqueous suspension or aqueous solvent-containing suspension of the individual components or their mixtures.

[0061] The invention also provides for the use of the pigment preparation for dyeing natural or synthetic high-molecular organic materials in the form of plastic masses, melts, spinning solutions, varnishes, coatings or printing inks.

[0062] Preferred is the use of dyeing (coloring) of nitrocellulose (NC)-based printing inks, in particular packaging gravure printing inks and packaging flexographic printing inks based on nitrocellulose. In addition to pure NC inks, hybrid printing inks can also be prepared using PU, PA, PVB and CAB binder systems and their combinations with NC concentrates.

[0063] The present invention also provides use of the pigment preparation for dyeing a color filter. DETAILED DESCRIPTION

[0064] The present invention is described in detail below in conjunction with embodiments.

[0065] Examples

[0066] Testing the pigments in NC ethanol gravure printing at increasing pigment concentrations

[0067] The following tests were performed on pigments specifically for packaging gravure inks and packaging flexographic inks based on nitrocellulose.

[0068] Preparation of dispersions using a shaker mill

[0069] First, a mixed solvent of 98 wt.% ethanol and 2.0 wt.% ethyl acetate was prepared. The standard and sample inks were prepared as follows: The inks were dispersed at 660 rpm using a shaker for 45 minutes.

[0070] After dispersion in the shaker, the concentrated ink was dispersed into a plastic beaker through a sieve and the pellets were removed.

[0071] Table 1: Composition of concentrated printing inks

[0072]

[0073] Determination of gloss and transparency

[0074] The printing ink was prepared as follows: 15 g of the dispersion concentrate and 0.75 g of Solvenon PM (1-methoxy-2-propanol) were weighed into a 150 ml plastic beaker and then shaken for 3 minutes in a "Disperser DAS200K" type disperser.

[0075] The concentrated inks of each type and sample were applied side by side to Leneta WF white test paper (gloss) and Leneta WF black stripe test paper (transparency) using a KCC doctor blade applicator (wet film thickness 12 μm), leaving as few streaks as possible.

[0076] The assessment is made visually. It is important to eliminate gloss when assessing clarity.

[0077] Table 2: Transparency Ratings

[0078]

[0079] Determine the flow time

[0080] The viscosity of the concentrated printing ink without "Solvenon PM" was determined. For this purpose, at least 50 g of concentrated printing ink were required. The dispersed concentrate was previously tempered in a water bath at 23° C. for 60 minutes.

[0081] The tempered printing ink concentrates are measured as follows using a Cup-Timer 243T (electronic flow time measuring device) with a correspondingly selected Zahn-Cup flow cup.

[0082] Preparation of mixed printing inks for colorimetric determination

[0083] 5.0 g of concentrated printing ink (see above)

[0084] 45.0g No. 1 varnish (NC ethanol blended varnish)

[0085] When the colorimetric determination is performed, the concentrated pigment is mixed with the NC blended varnish and the pigment content is adjusted to 2%. Under this condition, the absorption and reflection ratio of the mixed printing ink is conducive to colorimetric determination using a spectrophotometer.

[0086] The printing inks of the types and samples were applied streak-free side by side to Apco II / II test paper A using a KCC 7-stage doctor blade applicator (bar weight 2). For the colorimetric determination of the color properties according to CIELAB (color intensity, hue and purity), the reduction was measured at two different measuring positions using a template with a spectrophotometer (loss of light 3.7%) and evaluated.

[0087] Testing the compatibility of concentrated printing inks after dilution with ethyl acetate

[0088] Weigh the concentrated printing ink into a 150 ml PE beaker with a plugged lid. Add a mixed solvent consisting of 50 wt.% ethanol and 50 wt.% ethyl acetate while stirring, and shake well by hand.

[0089] Table 3: Composition of ester-stabilized inks

[0090]

[0091] The ester-stabilized ink diluted with the mixed solvent was temperature-controlled in a water bath (23° C.) for 60 minutes.

[0092] The ester compatibility of the printing ink was then first assessed visually as follows:

[0093] - Viscosity variation (low, medium or high viscosity)

[0094] - Agglomeration

[0095] - Phase separation

[0096] Determine the flow time:

[0097] After 24 hours, the tempered ester-stabilized printing inks were measured using a rotational viscometer (cone and plate arrangement) to determine viscosity, thixotropy and flowability.

[0098] Microscopic assessment of flocculation stability:

[0099] The flocculation stability of the ester stabilized printing inks was evaluated using a microscope at a magnification of 110X. The rating was from 1 (poor) to 5 (excellent).

[0100] Evaluate

[0101] The color properties were evaluated visually and colorimetrically according to the CIELAB formula (DIN ISO 18314-2).

[0102] Printing ink (mixed):

[0103] Reduction on APCO II / II Test Paper A: Colorimetric determination of color intensity, hue (dH), chroma (dC).

[0104] Table 4: Ingredients used

[0105]

[0106] Example 1

[0107] The procedure was similar to Example 4, but 2.62 g of HPP additive (89.6%) and 4.85 g of Arquad 16-29 (29%) were used.

[0108] Example 2

[0109] The procedure was similar to Example 4, but 2.36 g of HPP additive (89.6%), 4.37 g of Arquad 16-29 (29%) and 0.35 g of Solsperse 5000S were used.

[0110] Example 3

[0111] Add additives before grinding

[0112] In a Drais DCP SF12 stirred ball mill (manufacturer: Draiswerke GmbH, Mannheim), 3522 g of zirconium oxide beads with a diameter of 0.35-0.45 mm were charged as grinding media, 560 g of pigment raw material (Pigment Violet 23) and 15.72 g of HPP additive (89.6%) suspended in a mixture of 3430 g of water and 10.0 g of 33% sodium hydroxide solution were added and ground for 52 minutes at a rotation speed of 1470 rpm, a throughput of 600 ml / min, an input power of 4 kW and a temperature of 35° C. Then 17.17 g of Genamine DSAP (90%) were added and stirred at 25° C. for 1 hour.

[0113] Finally, the pH of the resulting 500 g bead mill suspension was adjusted to 6.5 by adding formic acid, 150 g aqueous isobutanol (85%) were added and stirred for a further 5 hours at 25° C. The mixture was then heated to 130° C. in an autoclave, kept at this temperature for 5 hours and then heated to 100° C. via the transition point to azeotropically distill off the isobutanol. After cooling to 60° C., the resulting pigment was separated by filtering the aqueous suspension, washed with demineralized water to a conductivity of less than 100 μS and then dried at 80° C.

[0114] Example 4

[0115] Variant with additive components added after finishing

[0116] In a Drais DCP SF12 stirred ball mill (manufacturer: Draiswerke GmbH, Mannheim), 3522 g of zirconium oxide beads with a diameter of 0.35-0.45 mm were filled as grinding media, and 560 g of pigment raw material (Pigment Violet 23) was added and suspended in a mixture of 3311 g of water and 129 g of 33% sodium hydroxide solution. The milling was carried out for 52 minutes at a rotation speed of 1470 rpm, a throughput of 600 ml / min, an input power of 4 kW and a temperature of 35°C.

[0117] Finally, the pH of the resulting 500 g bead mill suspension was adjusted to 6.5 by adding formic acid, 150 g aqueous isobutanol (85%) were added and initially stirred for a further 5 hours at 25° C. The mixture was then heated to 130° C. in an autoclave, kept at this temperature for 5 hours and then heated to 100° C. via a transition phase, the isobutanol being distilled off azeotropically. After cooling to 60° C., 1.96 g HPP additive (89.6%) were added to the distillation residue and, after stirring for 1 hour, 2.15 g Genamine DSAP (90%) were added and then stirred for a final further 2 hours at 60° C. The resulting pigment was isolated by filtering the aqueous suspension, washed with demineralized water to a conductivity of less than 100 μS and then dried at 80° C.

[0118] The same effect can be achieved by adding a pre-prepared mixture of the two additive components to isopropyl alcohol / water.

[0119] Example 5

[0120] Variants for adding additive components before finishing

[0121] In a Drais DCP SF12 stirred ball mill (manufacturer: Draiswerke GmbH, Mannheim), 3522 g of zirconium oxide beads with a diameter of 0.35-0.45 mm were filled as grinding media, and 560 g of pigment raw material (Pigment Violet 23) was suspended in a mixture of 3311 g of water and 129 g of 33% sodium hydroxide solution, and ground for 52 minutes at a rotation speed of 1470 rpm, a throughput of 600 ml / min, an input power of 4 kW, and a temperature of 35° C. After grinding, stirring was carried out at 25° C. for 1 hour.

[0122] Finally, the pH of the resulting 500 g bead mill suspension was adjusted to 6.5 by adding formic acid, 1.96 g HPP additive (89.6%) was added, stirring was continued at 25° C. for 1 hour, then 2.15 g Genamine DSAP (90%) was added and stirring was continued at 25° C. for another hour. 150 g aqueous isobutanol (85%) was then added and stirred at 25° C. for another 5 hours. The mixture was then heated to 130° C. in an autoclave, kept at this temperature for 5 hours, then heated to 100° C. via the transition point and the isobutanol was azeotropically distilled off. After cooling to 60° C., the resulting pigment was separated by filtering the aqueous suspension, washed with demineralized water to a conductivity of less than 100 μS and then dried at 80° C.

[0123] Comparative Example V2

[0124] The procedure was similar to Example 4, but processed immediately without additives.

[0125] Comparative Example V3

[0126] The procedure was similar to Example 4, but 11.22 g of Modifier #3C (22.3%) and 4.21 g of Arquad 16-29 (29%) were used; Modifier #3C was used as an aqueous suspension neutralized with dilute sodium hydroxide solution.

[0127] Comparative Example V4

[0128] The procedure was similar to Example 3, but 28 grams of Solsperse 5000S were used instead of the HPP additive; Genamin DSAP was not added in this example.

[0129] Comparative Example V5

[0130] The procedure was similar to Example 4, but using 2.12 g of sodium anthraquinone-2-sulfonate hydrate (97%) and 6.92 g of Arquad 16-29 (29%).

[0131] Comparative Example V6

[0132] The procedure was similar to Example 4, but without the addition of Genamin DSAP. In the visual color test, the 2.2% reduction in pigment was both redder (6 degrees redder) and darker (2 degrees darker) compared to comparative example V1.

[0133]

[0134]

[0135]

Claims

1. A pigment preparation comprising: a) CI Pigment Violet 23 of Formula I as base pigment; b) perylenetetracarboxylic acid diimide compounds of the general formula II containing at least one sulfonic acid group as pigment synergist, in: A is divalent>NR 1 or>NR 2 -SO 3 - X + Group; R 1 is a hydrogen atom, or C 1 -C 30 -alkyl, preferably C 1 -C 18 -alkyl, especially C 1 -C 4 -alkyl, or aryl, preferably phenyl, wherein aryl is unsubstituted or substituted with halogen such as chlorine or bromine, sulfonic acid, C 1 -C 4 -alkyl, such as methoxy or ethoxy C 1 -C 4 - mono- or poly-substituted alkoxy or phenylazo groups; R 2 Straight or branched chain C 1 -C 6 - alkylene, in particular ethylene or propylene; X + NR 3 R 4 R 5 R 6+ ,in, R 3 , R 4 , R 5 , R 6 H, straight chain or branched chain C 1 -C 30 -alkyl, phenyl or phenyl-C 1 -C 6 -alkyl.

2. The pigment preparation according to claim 1, It is characterized in that R 1 is methyl, R 2 C 2 -alkylene.

3. The pigment preparation according to claim 1 or 2, It is characterized in that R 3 is hexadecyl, R 4 , R 5 and R 6 are methyl.

4. The pigment preparation according to claim 1 or 2, It is characterized in that R 3 and R 4 is hexadecyl and / or octadecyl, R 5 and R 6 It is methyl.

5. The pigment preparation according to any one of claims 1 to 4, It is characterized in that The compound of general formula II is composed of a perylene tetracarboxylic acid diimide compound of general formula III containing at least one sulfonic acid group and a corresponding ammonium halide compound NR 3 R 4 R 5 R 6+ Hal - In pigment preparations, Among them, M + H + , metal cation or M m+ / m equivalent m-valent metal cation.

6. The pigment preparation according to any one of claims 1 to 5, comprising: a) 99.5 to 70 wt.% of a base pigment of formula I; b) 0.5 to 30 wt.% of a synergist of formula II; c) 0 to 5 wt.% of a nonionic surfactant; and d) 0-5 wt.% of common additives, The proportion of each component is based on the total weight of the preparation.

7. A method for preparing a pigment preparation according to any one of claims 1 to 6, It is characterized in that The surface structure of the base pigment a) is evenly coated with the pigment synergist b).

8. The method according to claim 7, It is characterized in that The pigment synergist b) is added to the coarsely crystalline raw base pigment a) during the fine dispersion of the coarsely crystalline raw base pigment a) during dry grinding or wet grinding.

9. The method according to claim 7, It is characterized in that The pigment synergist b) is added to the wet presscake of the base pigment a).

10. The method according to claim 7, It is characterized in that The pigment synergist b) is added to the finely divided base pigment a) during the solvent finishing process.

11. The method according to claim 7, It is characterized in that The pigment synergist b) is mixed mechanically in the dry state with the finely divided base pigment a).

12. Use of a pigment preparation according to any one of claims 1 to 6 for dyeing natural or synthetic high-molecular organic materials in the form of plastic masses, melts, spinning solutions, varnishes, coatings or printing inks.

13. The use according to claim 12 for dyeing or coloring nitrocellulose based printing inks.

14. Use of a pigment preparation according to any one of claims 1 to 6 for dyeing color filters.

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