| 摘要 |
A process for the preparation of 2,9-dimethylquinacridone pigments or mixed crystal pigments or mixtures of 2,9-dimethylquinacridone and quinacridones which in the two outer fused benzene rings can be substituted, characterized by the form of their crystalline particles having an average ratio of length to width of <2:1 and an average particle size of <0.4 mu m, by adding to the solution of 2,9-dimethylquinacridone before or during the finishing of the corresponding crude quinacridones of the quinacridones mentioned in water or solvent mixtures at temperatures from about 60 DEG to about 200 DEG C., in each case a compound of the general formula (I) Q[AY]n (I) in an amount of about 1 to 20% by weight, in which Q is a quinacridone radical which is unsubstituted or substituted, Y is an -NR4R5 group or the radical of a five-, six- or seven-membered heterocycle which contains one to three hetero atoms and can be substituted, R and R' are hydrogen or alkyl, and R1 to R5 are hydrogen and/or alkyl or alkylene, and n is a number from 1 to 4, the pigments themselves thus prepared and their use for the pigmenting of natural or synthetic materials and of lacquer systems.
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