EP2121695A1

EP2121695A1 - Diketopyrrolopyrrole cocrystals with high transparency

Info

Publication number: EP2121695A1
Application number: EP08707072A
Authority: EP
Inventors: Matthias Ganschow
Original assignee: Clariant Finance BVI Ltd
Current assignee: Clariant Finance BVI Ltd
Priority date: 2007-02-19
Filing date: 2008-01-17
Publication date: 2009-11-25
Also published as: US8318052B2; JP5235902B2; DE102007008140A1; WO2008101570A1; CN101578286B; US20100119966A1; KR20090122207A; CN101578286A; KR101488033B1; JP2010519349A

Abstract

The present invention relates to a pigment composition composed of compounds of the formula (I), (II) and (III) with a novel crystal modification, to their preparation and to the use of this novel product as a pigment. For many applications of organic pigments, for example the coloring of metallic lacquers or the use thereof in color filters, a very high transparency is required. To produce color filters, for example, particularly fine pigments are used, in order to substantially rule out the particle scattering which leads to a lowering of the contrast ratio. The commercially available products, however, do not always meet all requirements of the art. More particularly, there was a need for improvement with regard to the transparency and the associated fineness of the pigment crystals, and also the color purity (chroma).

Description

description

Diketopyrrolopyrrole mixed crystals with high transparency

The present invention relates to a pigment composition of compounds of formula (I), (II) and (III) having a novel crystal modification, their preparation and the use of this new product as a pigment.

For many applications of organic pigments, such as the coloring of metallic paints or the use in color filters, a very high transparency is required. To produce color filters, for example, finely divided pigments are used in order to largely rule out particle scattering, which leads to a reduction in the contrast ratio.

However, the commercially available commercial products do not always meet all the requirements of the art. In particular, there was a need for improvement in terms of transparency and the associated fineness of the pigment crystals and the color purity (chroma). From EP-AO 094 911 pigment compositions of diketopyrrolopyrroles (DPPs) are known, which can be prepared by mixed synthesis of two different nitriles A and B from succinic diesters, wherein 1 mole of succinic diester are reacted with 1 mole of two different nitriles. In Example 34, the reaction of 1 mole

Succinic acid ester with 1 mole of 3-chlorobenzonitrile and 1 mole of 4-chlorobenzonitrile described.

EP-A-0 181 290 discloses pigment compositions of diketopyrrolopyrroles (DPPs) which can be prepared by mixed synthesis from two different nitriles A and B from succinic diesters, the molar proportions of the nitriles disclosed in the examples being in the range from 88 to 99.9 mol. % A to 12 to 0.1 mol% B lie. Mixed syntheses of 3-chloro- and 4-chlorobenzonitriles are not specifically described.

EP-A-0 962499 (Example 42) discloses a pigment composition prepared by mixed synthesis of 50 mol% of 3-chloro and 50 mol% of 4-chlorobenzonitrile with succinic diesters in the presence of a crystal growth inhibitor.

WO 2002/085987, Example 1e) discloses a pigment composition prepared by mixed synthesis of 70 mol% of 3-chloro and 30 mol% of 4-chlorobenzonitrile and acid precipitation of the pigment alkali salt.

The object was to provide a diketopyrrolopyrrole pigment composition with an orange to red color, which has both a high transparency and fineness of the pigment crystals, as well as a high hue purity and brilliance.

It was found that a mixed crystal with a certain

Amount ratio of bis (4-X-phenyl) -diketopyrrolopyrrole (I), (3-chloro-phenyl) - (4-X-phenyl) -diketopyrrolopyrrole (II) and bis (3-chloro-phenyl) -diketopyrrolopyrrole (III) , As well as its manufacturing process solves this problem, surprisingly. The present invention relates to a mixed crystal of compounds of the formula (I), (II) and (III),

obtainable by reacting succinic diesters with a mixture of 97 to 80 mol% 3-chlorobenzonitrile and 3 to 20 mol% of 4-X-benzonitrile, with X = chlorine, methyl or nitrile, wherein the molar proportions of the 3-chloro and 4 X-benzonitriles in the sum of 100 mol%. Preferably, X is chlorine.

Preference is given to mixed crystals obtainable by reaction of succinic diesters with a mixture of 95 to 83 mol% of 3-chlorobenzonitrile and 5 to 17 mol% of 4-X-benzonitrile, the molar proportions of 3-chloro- and 4-X-benzonitriles in the sum of 100 mol%.

Surprisingly, it has been found that the mixed crystals according to the invention are present in a hitherto unknown new mixed-crystal modification.

For the purposes of the present invention, mixed crystals also include "solid

Solutions or solid solutions. The properties of the mixed crystals differ both from the properties of the individual components, as well as the properties of the physical mixtures of binzelkomponenten. In particular, the X-ray powder diagrams of the mixed crystals differ from those of the corresponding physical mixtures and from the sum of the powder diagrams of the individual compounds.

The new mixed-crystal modification is characterized by a different X-ray diffraction pattern from the previously known modifications obtained from mixed syntheses of 3- and 4-X-benzonitriles, namely by a characteristic line at 18.5 (Cu-K _α radiation, 2 theta). Values in degrees, measuring accuracy +/- 0.2 °).

The crystal modification according to the invention is characterized by the following X-ray powder diagram (Cu-K _α radiation, 2 theta values in degrees, measuring accuracy +/- 0.2 °, intensities: vs = very strong, s = strong, m = medium, w = weak , all other lines very weak):

2 theta: relative intensity:

5.8 s

13.2 s

14.9 W

16.3 W

18.5 m

20.9 W

24.1 m

25.7 s

27.4 s

29.7 m

The mixed crystals of the invention can be obtained in a fineness corresponding to a BET surface area of 90 to 150 m ² / g, preferably 92 to 130 m ² / g. The present invention also provides a process for the preparation of the mixed crystals according to the invention by reacting succinic diesters with 3-chloro- and 4-X-benzonitrile in the above proportions, in an organic solvent, in the presence of a strong base and at elevated temperature to form one

Pigmentalkalisalzes, subsequent hydrolysis of the pigment alkali metal salt in water and / or alcohol and optionally subsequent Löselfelfishish.

The total concentration of the nitriles in the organic solvent is suitably 0.5 to 5 mol / l.

The molar ratio of the strong base to the succinic diester is suitably 0.1 to 10 moles of base to 1 mole of succinic diester. The reaction temperature for the formation of the pigment alkali salt is expediently 60 to 140 ^° C., preferably 80 to 120 ^° C.

The succinic diesters to be used may be dialkyl, diaryl or monoalkylmonoaryl esters, it also being possible for the succinic acid dialkyl esters and diaryl esters to be asymmetrical. Preference is given to using symmetrical succinic diesters, in particular symmetrical succinic acid dialkyl esters. Lies a

Succinic acid diaryl esters or monoaryl monoalkyl esters, aryl in particular denotes unsubstituted or by 1, 2 or 3 substituents from the group halogen, such as chlorine, C 1 -C 6 -alkyl, such as methyl, ethyl, isopropyl, tert-butyl or tert-butyl. Amyl, or Ci-C ₆ alkoxy, such as methoxy or ethoxy, substituted phenyl. Aryl is preferably unsubstituted phenyl. If it is a succinic acid dialkyl ester or monoalkyl monoarylester, then alkyl may be unbranched, branched or cyclic, preferably branched, and preferably 1 to 18, in particular 1 to 12, especially 1 to 8 and particularly preferably 1 to 5 C-atoms contain. Alkyl is preferably sec- or tert-alkyl, for example isopropyl, sec-butyl, tert-butyl, tert-amyl, cyclohexyl, heptyl, 2,2-dimethylhexyl, octyl, decyl, dodecyl, tetradecyl or octadecyl ,

Examples of succinic diesters are dimethyl succinate, diethyl ester, dipropyl ester, dibutyl ester, dipentyl ester, dihexyl ester, -diheptyl esters, dioctyl esters, diisopropyl esters, di-sec-butyl esters, di-tert-butyl esters, di-tert-amyl esters, di- [1,1-dimethylbutyl] esters, di- [ 1, 1, 3,3-tetramethylbutyl] ester, di- [1, 1-dimethylpentyl] ester, di- [1-methyl-1-ethyl-butyl] ester, di- [1, 1 diethylpropyl] ester, diphenyl ester, di- [4-methylphenyl] ester, di- [2-methylphenyl] ester, di- [4-chlorophenyl] ester, di- [2,4- dichlorophenyl] -ester, -monoethylmonophenylester, -dicyclohexylester. In particular, symmetrical succinic acid dialkyl esters are used, wherein alkyl is branched and contains 3 to 5 carbon atoms. The reaction of the succinic diester with the nitrile is carried out in an organic solvent. Suitable solvents are, for example, primary, secondary or tertiary alcohols having 1 to 10 C atoms, such as methanol, ethanol, n-propanol, isopropanol, n-butanol, sec-butanol, tert-butanol, pentanols, such as n-pentanol or 2-methyl-2-butanol, hexanols such as 2-methyl-2-pentanol or 3-methyl-3-pentanol, 2-methyl-2-hexanol, 3-ethyl-3-pentanol, octanols such as 2,4 , 4-trimethyl-2-pentanol, cyclohexanol, or glycols, such as ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol or glycerol, or polyglycols, such as polyethylene glycols or polypropylene glycols, ethers, such as methyl isobutyl ether, tetrahydrofuran, dimethoxyethane or dioxane, glycol ethers, such as monomethyl or Monoethyl ether of ethylene or propylene glycol, diethylene glycol monomethyl ether or

Diethylene glycol monoethyl ether, butylglycols or methoxybutanol, dipolar aprotic solvents, for example acid amides such as dimethylformamide, N, N-dimethylacetamide or N-methylpyrrolidone, urea derivatives such as tetramethylurea, aliphatic or aromatic hydrocarbons such as cyclohexane or benzene or by alkyl, alkoxy, nitro or halogen substituted benzene such as toluene, xylene, ethylbenzene, anisole, nitrobenzene, chlorobenzene, o-dichlorobenzene or 1, 2,4-trichlorobenzene, aromatic N-heterocycles such as pyridine, picoline or quinoline, and hexamethylphosphoric triamide, 1, 3-dimethyl-2 -imidazolidinone, dimethyl sulfoxide or sulfolane.

The preparation of the pigment alkali salt takes place in the presence of a strong base. Suitable strong bases are, in particular, the alkali metals themselves, such as lithium, Sodium or potassium, or alkali metal amides, such as lithium, sodium or potassium amide, or alkali metal hydrides, such as lithium, sodium or potassium hydride, or alkaline earth or alkali metal alkoxides, in particular of primary, secondary or tertiary aliphatic alcohols having 1 to 10 C Such as lithium, sodium or potassium methylate, ethylate, n-propylate, isopropylate, n-butylate, sec-butoxide, tert-butylate, 2-methyl-2-butoxide, 2-methyl-2-pentylate, 3-methyl-3-pentylate, 3-ethyl-3-pentylate. Mixtures of the bases mentioned can also be used. Preference is given to alkali metal alkoxides, alkali particularly meaning sodium or potassium, and the alkoxide preferably being derived from a secondary or tertiary alcohol. Particularly preferred strong bases are therefore, for example, sodium or potassium isopropylate, sec-butoxide, tert-butylate and tert-amylate. The alkali metal alkoxides can also be prepared in situ by reacting the corresponding alcohol with the alkali metal, alkali metal hydride or alkali metal amide.

Hydrolysis of the pigment alkali salt may be carried out using water or one or more organic, protic solvents as hydrolysis agent. Protic solvents are e.g. Alcohols, preferably having 1 to 4 carbon atoms, such as methanol or ethanol, into consideration. It is also possible to use water and alcohol in any combination. The hydrolysis can also be carried out in the presence of organic aprotic solvents. The hydrolysis can be carried out directly by adding a hydrolysis agent to the reaction suspension, or indirectly, by adding the reaction suspension to the hydrolysis agent. The hydrolysis agents water and organic protic solvent can be added and / or presented in any order and also as mixtures. A simultaneous addition of individual components to a template is possible. It may be advantageous to use a buffer during hydrolysis, such as a phosphate, acetate, citric acid or triethanolamine buffer.

The temperature in hydrolysis may be from -20 ⁰ C to 200 ⁰ C, preferably from -5 to 180 ⁰ C, in particular 0 to 160 ⁰ C, if appropriate, the hydrolysis takes place under pressure. Reaction suspension and hydrolysis agents may also have different temperatures. For example, the hydrolysis can also be done by means of water vapor.

The total amount of hydrolysis agent is expediently an at least stoichiometric amount based on base. For example, water and / or an organic, protic solvent can be used between 0.5 and 50 parts by weight per 1 part of the resulting pigment.

The mixed crystals according to the invention can subsequently also be finished without the crystal modification changing. Depending on the finish conditions, the fine particles can grow again, so that depending on the desired application, the finishing conditions are adjusted accordingly. The finishing conditions which lead to more opaque particles are known to the person skilled in the art and are described, for example, in WO 02/085 987.

Finish conditions which largely preserve the fineness achieved according to the invention are described, for example, in EP-A-0 640 603. The procedure is preferably such that the pigment suspension obtained in the hydrolysis of the pigment alkali metal salt for 0.1 to 8 hours, in particular 0.5 to 6 hours, to a temperature of 50 to 150 ⁰ C, in particular 80 to 130 ⁰ C, optionally under pressure , is heated. Advantageous may be the presence of surfactants which inhibit crystal growth.

To facilitate the formation of mixed crystals, to stabilize the mixed crystals, to inhibit crystal growth, to improve the coloristic properties and / or to achieve certain coloristic effects, pigment dispersants, surface-active agents, defoamers, extenders or other additives can be added at any point in the process, if these do not affect the advantages of the invention. It is also possible to use mixtures of these additives. The addition of the additives can be done all at once or in several portions. The additives can on be added to any point of the synthesis or the various post-treatments, or after the post-treatments. The most appropriate time must first be determined by preliminary experiments.

It is also possible to carry out one or more of the mentioned process steps for the preparation of the pigment compositions according to the invention in a microreactor, such as e.g. in EP-A-1 257 602.

The mixed crystals of the invention can be used in principle for pigmenting all high molecular weight organic materials of natural or synthetic origin, for example of plastics, resins, paints, especially metallic paints, paints, printing inks, electrophotographic toners and developers, electret materials, color filters and inks, especially ink -Jet inks.

High molecular weight organic materials which can be pigmented with the mixed crystals according to the invention are, for example, cellulose compounds, such as, for example, cellulose ethers and esters, such as ethylcellulose, nitrocellulose, cellulose acetates or cellulose butyrates, natural binders, for example fatty acids, fatty oils, resins and the like

Conversion products, or synthetic resins, such as polycondensates, polyadducts, polymers and copolymers, such as aminoplasts, in particular urea and melamine-formaldehyde resins, alkyd resins, acrylic resins, phenolic resins and phenolic resins, such as novolaks or resols, urea resins, polyvinyls, such as polyvinyl alcohols, polyvinyl acetals, polyvinyl acetates or polyvinyl ethers,

Polycarbonates, polyolefins, such as polystyrene, polyvinyl chloride, polyethylene or polypropylene, poly (meth) acrylates and their copolymers, such as polyacrylic or polyacrylnithle, polyamides, polyesters, polyurethanes, coumarone-indene and hydrocarbon resins, epoxy resins, unsaturated resins (polyesters, acrylates) with the different hardening mechanisms, waxes, aldehyde and ketone resins, rubber, rubber and its derivatives and latices, casein, silicones and silicone resins; individually or in mixtures. It does not matter whether the mentioned high molecular weight organic compounds are present as plastic compositions, melts or in the form of spinning solutions, dispersions, paints, paints or printing inks. Depending on the intended use, it is advantageous to use the mixed crystals of the invention as a blend or in the form of preparations or dispersions.

Based on the high molecular weight organic material to be pigmented, the mixed crystals according to the invention are usually used in an amount of from 0.01 to 30% by weight, preferably from 0.1 to 20% by weight.

The mixed crystals according to the invention are also suitable as colorants in electrophotographic toners and developers, such as, for example, one- or two-component powder toners (also called one- or two-component developers), magnetic toners, liquid toners, polymerization toners and special toners. Typical toner binders are polymerization, polyaddition and

Polycondensation resins, such as styrene, styrene acrylate, styrene butadiene, acrylate, polyester, phenolic epoxy resins, polysulfones, polyurethanes, individually or in combination, as well as polyethylene and polypropylene, which may contain other ingredients, such as charge control agents, waxes or flow aids or be modified afterwards with these additions.

In addition, the mixed crystals according to the invention are as colorants in ink jet

Aqueous and non-aqueous based inks, and in inks which work according to the hot-melt method, suitable. Ink-jet inks generally contain a total of 0.5 to 15 wt .-%, preferably 1, 5 to 8 wt .-%, (calculated dry) one or more of the mixed crystals according to the invention.

Microemulsion inks are based on organic solvents, water and optionally an additional hydrotropic substance (interface mediator). Microemulsion inks generally contain from 0.5 to 15% by weight, preferably

1, 5 to 8 wt .-%, one or more of the mixed crystals according to the invention,

5 to 99% by weight of water and 0.5 to 94.5% by weight of organic solvent and / or hydrotrope compound. "Solvent based" ink jet inks preferably contain 0.5 to 15% by weight of one or more of the mixed crystals according to the invention, 85 to 99.5% by weight of organic solvent and / or hydrotropic compounds. Hot-melt inks are usually based on waxes, fatty acids, fatty alcohols or sulfonamides, which are solid at room temperature and liquid when heated, the preferred melting range between about 60 ⁰ C and 140 ⁰ C is about. For example, hot-melt ink-jet inks consist essentially of 20 to 90% by weight of wax and 1 to 10% by weight of one or more of the mixed crystals according to the invention. Furthermore, 0 to 20 wt .-% of an additional polymer (as a "dye remover"), 0 to 5 wt .-% dispersing aid, 0 to 20 wt .-% viscosity modifier, 0 to 20 wt .-% Piastifizierer, 0 to 10 wt % Of tackiness additive, 0 to 10% by weight of transparency stabilizer (prevents, for example, crystallization of the waxes) and 0 to 2% by weight of antioxidant.

In particular, the mixed crystals according to the invention are colorants for color filters, both for additive and for subtractive color generation, such as in electro-optical systems such as television screens, liquid crystal displays, charge coupled devices, plasma displays or electroluminescent displays, which in turn can be active (twisted nematic) or passive (supertwisted nematic) ferroelectric displays or light-emitting diodes, as well as colorants for electronic inks ("electronic inks" or "e-inks") or "electronic paper"("e-paper") suitable. In the production of color filters, both reflective and transparent color filters, pigments in the form of a paste or as pigmented photoresists in suitable binders (acrylates, acrylic esters, polyimides, polyvinyl alcohols, epoxies, polyesters, melamines, gelatin, caseins) on the respective LCD components (eg TFT-LCD = Thin Film Transistor Liquid Crystal Displays or eg ((S) TN-LCD = (Super) Twisted Nematic-LCD) In addition to a high thermal stability, a stable paste or a pigmented photoresist also has a high pigment purity Requirement. In addition, the pigmented color filters can also through

Ink jet printing process or other suitable printing process can be applied.

The red shades of the mixed crystals according to the invention are particularly well suited for the color filter color set red-green-blue (R ₁ G ₁ B) - These three colors are present as separate color points next to each other, and result from backlit a full-color image.

Typical colorants for the red color point are pyrrolopyrrole, quinacridone and azo pigments, e.g. Cl. Pigment Red 254, Cl. Pigment Red 209, Cl. pigment

Red 175 and C.!. Pigment Orange 38, single or mixed. For the green

Color point typically phthalocyanine colorants are used, such.

Cl. Pigment Green 36 and Cl. Pigment Green 7.

If necessary, additional colors can be added to the respective color dots for nuancing. For the red and green color is preferred with

Yellow mixed, for example with Cl. Pigment Yellow 138,139,150,151, 180 and

213th

Finally, it is also possible, the mixed crystal pigment according to the invention by dry mixing with organic or inorganic masses,

Granules, fibers, powders and other pigments to process mixtures.

In the following examples, percentages are percentages by weight and parts by weight unless otherwise stated. The

X-ray powder diagrams were measured with Cu-K _α radiation, 2 theta values in degrees, measuring accuracy +/- 0.2 °, for which intensities mean: vs = very strong, s = strong, m = medium, w = weak. Comparative Example 1 (50% 3-chlorobenzonitrile, 50% 4-chlorobenzonitrile):

It is a pigment mixture according to EP-A-O 094 911, Example 34 of a

Mixture of 50 mol% of 3-chlorobenzonitrile and 50 mol% of 4-chlorobenzonitrile produced.

The pigment obtained has a BET surface area of 56 m ² / g and is characterized in

X-ray powder diagram by the following characteristic lines:

2 theta: relative intensity:

5.8 s

11, 8 W

13.1 m

14.4 s

17.6 m

20.9 W

22.1 W

24.1 m

24.5 m

26.9 s

28.9 m

The characteristic new line of the crystal modification according to the invention at 18.5 ° (+/- 0.2) 2 theta is not visible.

Comparative Example 2 (70% 3-chlorobenzonitrile, 30% 4-chlorobenzonitrile, acid precipitation):

The pigment is prepared according to WO 02/085987 A1, Example 1 e from a mixture of 70 mol% of 3-chlorobenzonitrile and 30 mol% of 4-chlorobenzonitrile. The pigment obtained has a BET surface area of 87 m ² / g and is characterized in the X-ray powder diagram by the following characteristic lines:

2 theta: relative intensity:

5.8 s

13.2 m

14.3 m

17.9 m

22.2 W

24.1 m m

26.2 m

27.2 s

29.5 W

Comparative Example 3 (70% 3-chlorobenzonitrile, 30% 4-chlorobenzonitrile, precipitation on water): 21.7 parts of 3-chlorobenzonitrile and 9.3 parts of 4-chlorobenzonitrile are dissolved in 30% sodium amylate (prepared from 9.3 parts of sodium and 143 parts of amyl alcohol) and heated to 100 ⁰ C. 30 parts of diisopropyl succinate are added within two hours. After a further four hours at 100 ⁰ C, the Pigmentalkalisalz suspension is cooled to 80 ⁰ C and added to 60 ⁰ C hot water. The pigment suspension is then heated for conditioning for five hours at 95 ⁰ C, filtered off, washed with methanol and water and dried in a drying oven at 75 ⁰ C. This gives an orange-red pigment. The pigment obtained has a BET surface area of 73 m ² / g and is characterized in the X-ray powder diagram by the following characteristic lines:

2 theta: relative intensity:

5.9 s

13.1 m

14.5 m

17.9 m

21, 8 W

24.1 m

25.9 s

26.2 m

27.2 s

29.7 W

Example 1 (mixed crystal of 80 mol% of 3-chlorobenzonitrile, 20 mol% of 4-chlorobenzonitrile):

The pigment is prepared analogously to Comparative Example 3, except that 24.8 parts

3-chlorobenzonitrile and 6.2 parts of 4-chlorobenzonitrile be implemented.

After isolation and washing with methanol and water, an orange-red pigment is obtained.

The pigment obtained has a BET surface area of 103 m ² / g and is much finer in particle size than the pigments from Comparative Examples 1 and 3. It is characterized in the X-ray powder diagram by the following characteristic lines:

2 theta: relative intensity:

5.7 S 13.2 S 2 theta: relative intensity:

14.9 W

16.3 W

18.4 m

20.9 W

24.2 m

25.8 s

27.3 s

29.8 m

The characteristic novel line of the crystal modification according to the invention at 18.5 ° (+/- 0.2) 2 theta is present.

Example 2 (mixed crystal of 83 mol% 3-chlorobenzonitrile, 17 mol% 4-chlorobenzonitrile):

The pigment is prepared analogously to Comparative Example 3, except that 25.8 parts of 3-chlorobenzonitrile and 5.2 parts of 4-chlorobenzonitrile are used. This gives an orange-red pigment.

The pigment obtained has a BET surface area of 98 m ² / g and is much finer in particle size than the pigments from Comparative Examples 1 and 3. It is characterized in the X-ray powder diagram by the following characteristic lines:

2 theta: relative intensity:

5.8 s

13.2 s

14.9 W

16.3 W

18.5 m

20.9 W

24.2 m

25.8 s 2 theta: relative intensity:

27.3 S 29.8 m

Example 3 (mixed crystal of 92 mol% of 3-chlorobenzonitrile, 8 mol% of 4-chlorobenzonitrile):

The pigment is prepared analogously to Comparative Example 3, except that 28.4 parts of 3-chlorobenzonitrile and 2.6 parts of 4-chlorobenzonitrile are used. This gives an orange-red pigment.

The pigment obtained has a BET surface area of 99 m ² / g and is much finer in particle size than the pigments from Comparative Examples 1 and 3. It is characterized in the X-ray powder diagram by the following characteristic lines:

2 theta: relative intensity:

5.9 s

13.2 s

14.9 W

16.3 W

18.6 m

20.9 W

24.1 m

25.7 s

27.4 s

29.8 m

The characteristic novel line of the crystal modification according to the invention at 18.5 ° (+/- 0.2) 2 theta is present. Example 4 (mixed crystal of 83 mol% of 3-chlorobenzonitrile, 17 mol% of 4-methylbenzonitrile):

The pigment is prepared analogously to Comparative Example 3, except that 25.8 parts of 3-chlorobenzonitrile and 5.2 parts of 4-methylbenzonitrile are used. This gives an orange-red pigment.

The resulting pigment has a BET surface area of 102 m ² / g and is much finer in particle size than the pigments of Comparative Examples 1 and 3. The characteristic novel line of the inventive crystal modification at 18.5 ° (+/- 0.2) 2 theta is available.

Example 5 (mixed crystal of 83 mol% of 3-chlorobenzonitrile, 17 mol% of terephthalonitrile):

The pigment is prepared analogously to Comparative Example 3, except that 25.8 parts of 3-chlorobenzonitrile and 5.2 parts of terephthalonitrile are used. This gives an orange-red pigment.

The resulting pigment has a BET surface area of 109 m ² / g and is much finer in particle size than the pigments of Comparative Examples 1 and 3.

The BET surface areas of the pigments prepared in the above Examples are shown in the following table.

Examples 1 to 5 according to the invention are very much finer crystalline than Comparative Examples 1 to 3.

Application examples:

To determine the color strength and the transparency of the pigment mixtures, the pigments obtained were completely dispersed in a transparent alkyd-melamine stoving lacquer system.

To determine the transparency of the pigmented alkyd melamine stoving lacquer was applied as a solid paint together with the sample to be compared side by side on a white card with black cardboard and baked after 30 min air drying for 30 min at 140 ⁰ C. To assess the transparency, the opacity of the two applied pigments over a black background was compared.

To determine the color strength, a whitening varnish was prepared by mixing 6.0 g of the alkyd-melamine solid paint with 20.0 g of a 30% white paint. The whitening lacquer obtained was applied together with the sample to be compared side by side on a white card and baked after 30 min air drying for 30 min at 140 ⁰ C. The color intensity and its measurement is defined in accordance with DIN EN ISO 787-26.

The color strengths, chroma (color purity) and transparency of the pigments prepared in the above examples are given in the table below. As a standard for the color strength (100%), the chroma ΔC (color purity) (ΔC = 0) and the transparency, the pigment from Example 1 was used.

Transparency was assessed as follows. + Vl much more opaque

+ V much more opaque

+ IV significantly more opaque

+ III noticeably more opaque

+ Il a bit more hiding + l a bit more covering

/ = / about how

-I a bit more transparent

-Il something more transparent

-III noticeably more transparent -IV much more transparent

-V much more transparent

-VI significantly more transparent

Comparative Examples 1, 2 and 3 are much cloudier (ΔC << -1, 0) than Examples 1 to 3 according to the invention. Comparative Examples 1 and 3 are also much more opaque than Examples 1 to 3 according to the invention.

Claims

claims:

1) mixed crystal of compounds of the formula (I) ₁ (II) and (III),

obtainable by reacting a succinic diester with a mixture of 97 to 80 mol% 3-chlorobenzonitrile and 3 to 20 mol% of 4-X-benzonitrile, with X = chlorine, methyl or nitrile, wherein the molar proportions of the 3-chloro and 4 X-benzonitriles in the sum of 100 mol%.

2) mixed crystal according to claim 1, obtainable by reacting a succinic diester with a mixture of 95 to 83 mol%

3-chlorobenzonitrile and 5 to 17 mol% of 4-X-benzonitrile, wherein the molar proportions of 3-chloro and 4-X-benzonitriles in the sum of 100 mol%.

3) mixed crystal according to claim 1 or 2, characterized in that X is chlorine.

4) mixed crystal according to one or more of claims 1 to 3, characterized by a characteristic line in X-ray diffraction diagram at 2Theta 18.5 ° +/- 0.2 °, measured with Cu-K _α radiation.

5) mixed crystal according to one or more of claims 1 to 4, characterized by the lines in the X-ray powder diagram (Cu-K _x radiation, 2 theta values in degrees, measuring accuracy +/- 0.2 °, intensities: vs = very strong, s = strong, m = medium, w = weak):

2 theta: relative intensity:

5.8 s

13.2 s

14.9 W

16.3 W

18.5 m

20.9 W

24.1 m

25.7 s

27.4 s

29.7 m

6) mixed crystal according to one or more of claims 1 to 5, characterized by a BET surface area of 90 to 150 m ² / g.

7) A process for producing a mixed crystal according to one or more of claims 1 to 6 by reacting a succinic diester with 97 to 80 mol% of 3-chlorobenzonitrile and 3 to 20 mol% of 4-X-benzonitrile, in an organic solvent, in the presence of a strong base and at elevated temperature to form a pigment alkali salt, followed by hydrolysis of the pigment alkali salt in water and / or alcohol and optionally subsequent solvent finish. 8) Method according to claim 7, characterized by implementation of a

Succinic diester with 95 to 83 mol% of 3-chloro-benzonitrile and 5 to 17 mol% of 4-X-benzonitrile.

9) Use of a mixed crystal according to one or more of

Claims 1 to 6 for pigmenting high molecular weight organic materials of natural or synthetic origin.

10) Use according to claim 9 for pigmenting plastics, resins, paints, paints, printing inks, electrophotographic toners and

Developers, color filters and integers.

11) Use according to claim 9 or 10 for pigmenting color filters, metallic paints and ink-jet inks.