Use of aromatic compounds as phase directors and particle size reducers for quinacridone pigments
AssigneeCiba Specialty Chemicals Corporation
InventorsShivakumar Basalingappa Hendi, Suruliappa Gowder Jeganathan, James Barry Ganci
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Abstract
The present invention relates to a process for producing alpha, gamma-I, gamma-II and gamma-III crystal modifications of quinacridone and transparent quinacridone pigments including the solid solutions of various quinacridones, using a variety of tris-aryl-s-triazines, particularly resorcinol triazine derivatives, or aromatic- or heteraromatic-compounds having at least one hydroxyl or keto group bonded to the ring, as an additive, prior to or concurrently with the oxidation of corresponding dihydroquinacridone salts.
Claims12
A process for producing a quinacridone pigment according to formula B
- 16
- or a solid solution thereof,
- comprising oxidizing a salt of a corresponding 6,13-dihydroquinacridone of formula A or a mixture of two or more 6,13-dihydroquinacridones of formula A
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- in which X and Y are independently 1 or 2 substituents selected from the group consisting of H, F, Cl, C1-C4, alkyl and C1-C4 alkoxy, in the presence of at least one (hetero)aromatic hydroxyl or keto group containing compound that does not contain a pigment moiety and an oxidizing agent.
A composition comprising a high molecular weight organic material and an effective pigmenting amount of a composition according to clam 7.
Dependencies are inferred from the claim text.