NOVEL 2,9-DICHLOROQUINACRIDONE IN PLATE-LIKE FORM Russian patent published in 2012 - IPC C09B67/52 C09B67/10 D06P1/44 

FIELD: chemistry.

SUBSTANCE: invention relates to a novel 2,9-dichloroquinacridone in plate-like form, which is meant for pigmentation of organic material. 2,9-dichloroquinacridone in plate-like form has length of 1-45 mcm, width of 0.1-20 mcm and thickness of 0.01-5 mcm. Said pigment has colour hue h for attenuation ≤31, luminosity L* for transmission ≥20. When illumination angle and the viewing angle (specular angle) change from 45°/110° (+25°) to 45°/90° (+45°) the value b* falls, and the value a* increases. The method of producing said 2,9-dichloroquinacridone in plate-like form and pigment form involves (a) dispersion and partial dissolution of crude 2,9-dichloroquinacridone in a polar solvent in the presence of a base at temperature from 100°C to boiling point of the solvent, and (b) precipitation of 2,9-dichloroquinacridone in plate-like form by adding water while lowering temperature.

EFFECT: obtaining 2,9-dichloroquinacridone in plate-like form, having colour properties given above in the CIELAB colour coordinate system, from crude 2,9-dichloroquinacridone without an aliphatic long-chain thiol.

8 cl, 3 dwg, 2 ex