Surface-active compounds based on modified castor oil fatty substances

The demands on the properties of pigments, in particular in the fields of emulsion paints and printing inks, which constantly become more specific have made it necessary to develop selective and environmentally friendly dispersing, emulsifying and coupling auxiliaries. The compounds according to the invention are esterification and/or arylation products prepared from natural or modified castor oil or ricinoleic acids, which products are alkoxylated and, if desired, linked by esterification with dicarboxylic acids to give recurring structural units. If desired, the terminal hydroxyl groups of these modified alkoxylates of castor oil fatty substances have been esterified with fatty acids, aromatic carboxylic acids and/or resin acids and any free hydroxyl groups which may be present have preferably been reacted with dicarboxylic acids and sulfite to give the corresponding monoesters containing anionic radicals. The compounds according to the invention are suitable for a wide range of applications in the field of surface-active agents, for example in the preparation of azo pigments, emulsion paints and printing inks, for improving the coloristic and rheological properties. The compounds according to the invention are particularly compatible with the environment owing to their biodegradability.