Crystal modification of C.I. Pigment Red 53:2 (.delta.-phase)

A process for the preparation of C.I. Pigment Red 53:2 of the formula (I) ##STR5## in which M is a cation, with the proviso that at least 50% of the cations are calcium ions,

• in the .delta.-modification, which has the following characteristic reflections in the X-ray powder diffraction pattern, measured using Cu--K.sub..alpha. radiation:
• ______________________________________ .delta.:
• 2.THETA. d Relative intensity (in %) ______________________________________ 3.3 26.6 32 4.7 18.7 100 7.5 11.9 14 9.4 9.3 19 10.5 8.4 13 13.8 6.4 10 14.2 6.2 9 14.9 5.9 10 16.7 5.3 11 17.6 5.0 9 18.1 4.9 16 18.9 4.7 10 20.4 4.3 7 21.1 4.2 9 22.1 4.0 9 22.7 3.9 12 23.1 3.8 9 23.6 3.8 13 24.1 3.7 9 24.9 3.6 10 25.5 3.5 23 26.3 3.4 9 27.7 3.2 9 28.1 3.2 6 28.9 3.1 6 30.4 2.9 6 ______________________________________
• wherein .beta.-naphthol is reacted with the diazonium salt of the formula (2) ##STR6## in which M.sup.1 is hydrogen or a cation equivalent and X is an anion
• and with a calcium salt in the presence of chlorobenzene.

A process for the preparation of C.I. Pigment Red 53:2 of the formula (I) ##STR7## in which M is a cation, with the proviso that at least 50% of the cations are calcium ions,

• in the .delta.-modification, which has the following characteristic reflections in the X-ray powder diffraction pattern, measured using Cu--K.sub..alpha. radiation:
• ______________________________________ .delta.:
• 2.THETA. d Relative intensity (in %) ______________________________________ 3.3 26.6 32 4.7 18.7 100 7.5 11.9 14 9.4 9.3 19 10.5 8.4 13 13.8 6.4 10 14.2 6.2 9 14.9 5.9 10 16.7 5.3 11 17.6 5.0 9 18.1 4.9 16 18.9 4.7 10 20.4 4.3 7 21.1 4.2 9 22.1 4.0 9 22.7 3.9 12 23.1 3.8 9 23.6 3.8 13 24.1 3.7 9 24.9 3.6 10 25.5 3.5 23 26.3 3.4 9 27.7 3.2 9 28.1 3.2 6 28.9 3.1 6 30.4 2.9 6 ______________________________________
• wherein C.I. Pigment Red 53:2 which is present wholly or partially in the .alpha.-modification is heated, together with chlorobenzene or a chlorobenzene/water mixture, to a temperature of from 40 to 200.degree. C., and then cooled to a temperature of from -20 to +90.degree. C., optionally water, a second solvent having low dissolving power or a combination thereof are added and, optionally, an acid, an alkali or a salt is added.

A process for the preparation of C.I. Pigment Red 53:2 of the formula (I) ##STR8## in which M is a cation, with the proviso that at least 50% of the cations are calcium ions,

• in the .delta.-modification, which has the following characteristic reflections in the X-ray powder diffraction pattern, measured using Cu--K.sub..alpha. radiation:
• ______________________________________ .delta.:
• 2.THETA. d Relative intensity (in %) ______________________________________ 3.3 26.6 32 4.7 18.7 100 7.5 11.9 14 9.4 9.3 19 10.5 8.4 13 13.8 6.4 10 14.2 6.2 9 14.9 5.9 10 16.7 5.3 11 17.6 5.0 9 18.1 4.9 16 18.9 4.7 10 20.4 4.3 7 21.1 4.2 9 22.1 4.0 9 22.7 3.9 12 23.1 3.8 9 23.6 3.8 13 24.1 3.7 9 24.9 3.6 10 25.5 3.5 23 26.3 3.4 9 27.7 3.2 9 28.1 3.2 6 28.9 3.1 6 30.4 2.9 6 ______________________________________
• wherein C.I. Pigment Red 53:2 which is present wholly or partly in the .alpha.-modification is kneaded or milled in the presence of chlorobenzene or a chlorobenzene/water mixture at a temperature of from 40 to 200.degree. C.

A method of pigmenting coatings, plastics, printing inks, electrophotographic toners and developers, powder coatings, inkjet inks, aqueous pigment preparations and seeds comprising the step of adding a C.I. Pigment Red 53:2 of the formula (I) ##STR9## in which M is a cation, with the proviso that at least 50% of the cations are calcium ions,

• in the .delta.-modification, which has the following characteristic reflections in the X-ray powder diffraction pattern, measured using Cu--K.sub..alpha. radiation:
• ______________________________________ .delta.:
• 2.THETA. d Relative intensity (in %) ______________________________________ 3.3 26.6 32 4.7 18.7 100 7.5 11.9 14 9.4 9.3 19 10.5 8.4 13 13.8 6.4 10 14.2 6.2 9 14.9 5.9 10 16.7 5.3 11 17.6 5.0 9 18.1 4.9 16 18.9 4.7 10 20.4 4.3 7 21.1 4.2 9 22.1 4.0 9 22.7 3.9 12 23.1 3.8 9 23.6 3.8 13 24.1 3.7 9 24.9 3.6 10 25.5 3.5 23 26.3 3.4 9 27.7 3.2 9 28.1 3.2 6 28.9 3.1 6 30.4 2.9 6 ______________________________________
• to a coating, plastic, printing ink liquor, electrophotographic toner and developer, powder coating, inkjet ink liquor, aqueous pigment preparation or seed to be pigmented.