Stabilization of anionic indole dyestuffs

US4245995A · kind A · utility

Assignee

• BAYER HEALTHCARE LLC · DE

Inventors

• Herbert Hugl
• Hans Otten · London, CA
• Hans-Werner Petroll · Leverkusen, DE
• Karlheinz Wolf · Leverkusen, DE

Key dates

• Filing date: Feb 9, 1978
• Grant date: Jan 20, 1981
• Expiry date: Feb 9, 1998

Classification

• Technology area (CPC D): Textiles; Paper
• CPC primary: D06P3/241
• WIPO field: Basic materials chemistry
• WIPO sector: Chemistry

Abstract

Azo dyestuffs which contain, as the coupling component an indole of the formula ##STR1## wherein R denotes an optionally substituted alkyl radical, an optionally substituted aryl radical or an optionally substituted aralkyl radical, and the benzene ring A can be further substituted, frequently exhibit an undesired irreversible change in the color shade in acid solutions, which surprisingly can be prevented by adding nitrogen-containing complex-forming substances.