Patent ID: 6664036
Filing Date: 2003-12-16
Classification: G03C

Abstract:
An aqueous, homogeneous, single-part color developing concentrate having a pH of from about 9 to about 13 and comprising:a) at least 0.05 mol/l of an N,N-dialkyl-p-phenylenediamine color developing agent in free base form, b) at least 0.1 mol/l of an antioxidant composition for said color developing agent that comprises an N,N-dialkyl- or N,N-diarylhydroxylamine derivative having at least one solubilizing group, and c) a water-miscible or water-soluble organic co-solvent that has a molecular weight of from about 100 to about 400, is present in said concentrate at a concentration such that the weight ratio of water to said organic co-solvent is from about 7:1 to about 30:1, and is represented by the following Structure I: Yâ€”Zâˆ’M+â€ƒâ€ƒ(I) â€ƒwherein Y is uncharged in the pH range of from 10 to 11 and is an alkyl group having 4 to 16 carbon atoms, a cycloalkyl group having 5 to 10 carbon atoms in the ring, an alkylene group having 1 to 6 carbon atoms that is additionally substituted with a cycloalkyl group, a carbocyclic aryl group or a heterocyclic group containing 1 to 3 hetero atoms, Zâˆ’ is a monovalent group comprising a single negative charge or an acidic group that is ionized to a single negative charged group at pH of 10 or more, and M+ is a monovalent cation.