(EN) Pigment of formula wherein R1 is CONR4R5 or C(=NR6)NR7R8, R2, R3, R4 and R5 are each independently of the others H, C1-C5alkyl, or phenyl which is unsubstituted or substituted from 1 to 5 times by C1-C5alkyl or by halogen, R6 is phenyl which is unsubstituted or substituted from 1 to 4 times by C1-C5alkyl or by halogen, R7 is H or C1-C5alkyl, and R8 is a direct bond or a carbonyl bridge to R6, which pigment consists of primary particles the average aspect ratio of which is from 4 to 1, preferably from 3.5 to 1, especially from 3 to 1, and /or the ellipses equivalent to the contours of the primary particles on a two-dimensional electron microscopic image have an average numerical eccentricity Epsilon of from 0 to 0.80, the numerical eccentricity Epsilon being defined as (formula), wherein a is the semimajor axis and b is the semiminor axis of the equivalent ellipse. That pigment preferably has a narrow particle size distribution and is, as are analogous pigments, prepared by a novel process. The invention relates also to a process for the preparation of that pigment, wherein R1CH2CN or (formula) is dispersed in an acidic aqueous medium containing from 70 to 99 % by weight water, preferably in the presence of a dispersant, and is reacted with solid (formula).
(ZH) 式(I)或式(II)，优选式(III)的颜料，其中R1是CONR4R5或C(＝NR6)NR7R8，R2、R3、R4和R5各自独立地为H、C1-C5烷基、或者未取代的或被C1-C5烷基或卤素取代1-5次的苯基，R6是未取代的或被C1-C5烷基或卤素取代1-4次的苯基，R7是H或C1-C5烷基，和R8是连到R6的直接键或羰基桥，所述颜料由平均形态比为4-1，优选3.5-1，尤其3-1的初级粒子组成，和/或等效于在二维电子显微图像上初级粒子轮廓的椭圆的平均数值偏心率ε为0-0.80，数值偏心率ε定义为式(IV)，其中a是等效椭圆的半长轴和b是等效椭圆的半短轴。该颜料优选具有窄的粒度分布，与类似的颜料一样，通过新方法制备。本发明还涉及制备该颜料的方法，其中优选在分散剂的存在下将R1CH2CN或式(V)分散到含有70-99重量％的水的酸性含水介质中，并使其与式(VI)、(VII)或式(VIII)的固体反应。![]()