Stabilization of pyrrolopyrrole pigments

U.S. Patent Number: 5389141

Abstract: Pigment compositions comprising a) at least one pyrrolo[3,4-c]pyrrole pigment of the formula ##STR1## in which A and B, independently of one another, are isocyclic or heterocyclic aromatic radicals, and D is an oxygen or sulfur atom, and b) from 1 to 100% by weight, based on the pigment, of a nitroxyl compound or of an acid-addition salt thereof. These pigment compositions are distinguished by excellent light stability and weathering resistance.

Inventors: Chassot; Laurent (Praroman, CH)

Assignee: Ciba-Geigy Corporation (Ardsley, NY)

Application Number: 08/171,896

Issued: 1995-02-14

Expired: 2007-02-14

Classes: 106/498 ; 106/493; 106/494; 106/500; 106/505; 548/426

Field of search: 548/426 106/493,494,498,500,505

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