| abstract |
A process for preparing a black colorant, preferably a black pigment, characterized in that the compound of formula (i) is reacted with a compound of formula (ii) in a molar ratio of 1: 2 in the presence of a catalyst having pK ≦ 4.5 in 25 ° C. water. It provides a manufacturing method. For the definition of R 1 to R 7 , the above description is referred to; Preferably all are H. Similarly, new crystal polymorphs obtainable by this method, and single phase mixed crystals are claimed. Also complimentary compositions are claimed. Such compositions exhibit improved photostability in plastics with basic photostabilizers when pigmented with the colorants of the invention as compared to those with known black pigments such as carbon black. In addition, the specification also relates to the use of the black colorants of the invention for paints, printing inks and whole plastics, and to herbicidal films, instrument panels, nonwovens, garden furniture articles or building industrial members pigmented with the colorants. Formula (i) Formula (ii) |