| abstract |
The invention relates to a process for preparing pigments, which comprises: subjecting a crude pigment or mixture of crude pigments and a crystalline inorganic salt of mixture of crystalline inorganic salts together, essentially in the absence of other constituents, to the action of a rotor having a tangential speed of at least 10 m/s, so that a temperature of at least 80°C is attained by means of friction effects; and subsequently kneading the product of this treatment with an organic liquid, during which it is possible if desired to add additional substances selected from the group consisting of inorganic salts, inert additives and colorants. These pigments and their use in polymers, printing inks and colours filters are also claimed. The invention in particular relates to a novel pigment form of Pigment Violet 23 represented by Formula (I), obtained by above-mentioned process and having higher colour strength and colour saturation as well as excellent other applications properties in particular in printing inks. The invention also relates to a highly crystalline novel form of Pigment Red 254 represented by Formula (II), obtained by above-mentioned process, too, and having a steep slope on the bathochromic side of the absorption spectrum's maximum, and the use thereof in particular in colour filters. |