Stable liquid aqueous composition of a water-soluble fiber-reactive azo dyestuff, containing a buffer substance, the dyestuff having been prepared by diazotization with a nitrite and coupling in the absence of acid

US4118184A · kind A · utility

Assignee

• Hoechst GmbH · DE

Inventors

• Konrad Opitz · Liederbach, DE
• Josef Landler · Hofheim, DE
• Erhard Worfel

Key dates

• Filing date: Jun 17, 1977
• Grant date: Oct 3, 1978
• Expiry date: Jun 17, 1997

Classification

• Technology area (CPC C): Chemistry; Metallurgy
• CPC primary: C09B62/018
• WIPO field: Basic materials chemistry
• WIPO sector: Chemistry

Abstract

Concentrated dyeing compositions containing up to 45% by weight of one or more metal-free or metal complex azo dyestuffs containing one or more sulfo groups and one or more reactive groups, and containing buffer substances and having a pH of from 3 to 7, which may easily be prepared by diazotization and coupling of stoichiometrical amounts of a diazotizable amino compounds with a stoichiometrical amount of a nitrite and with a coupling component without addition of an acid but with the proviso that at least the diazo or coupling component contain at least one free acid group, such as sulfo group; these compositions are salt-free or practically salt-free and are very well suitable for the preparation of usual dyeing liquors and printing pastes useful in dyeing wool, silks, polyamide fibers and natural or regenerated cellulose.