Leather dyeing agents and their preparation: membrame separation of dye mother liquor

US4402701A · kind A · utility

Assignee

• BAYER HEALTHCARE LLC · DE

Inventors

• Harald Gleinig · Odenthal, DE
• Hans-Heinz Molls · Leverkusen, DE
• Jochen Koll · Odenthal, DE
• Gottfried Dick · Leverkusen, DE
• Reinhold Hornle
• Friedrich Kunert · Leverkusen, DE

Key dates

• Filing date: Sep 21, 1981
• Grant date: Sep 6, 1983
• Expiry date: Sep 21, 2001

Classification

• Technology area (CPC C): Chemistry; Metallurgy
• CPC primary: C09B67/0072
• WIPO field: Basic materials chemistry
• WIPO sector: Chemistry

Abstract

Leather dyeing agents, which can be obtained by concentrating, by means of a membrane separation process, the mother liquors, which are produced in the salting-out process in the preparation of organic dyestuffs which are water-soluble or which contain groups imparting water-solubility, the mother liquors having an extinction in the absorption maximum which is .gtoreq.500, with a layer thickness of 10 cm, and by drying the concentrate, if appropriate.