| abstract |
The invention relates to a condensation product obtainable by reaction ofn a1) at least one aromatic or heteroaromatic, where the aromatic or heteroaromatic is substituted by at least one hydroxyl group (—OH) and at least one carboxyl group (—COOH), and where the hydroxyl and/or carboxyl group can be present in salt form, a2) at least one carbonyl compound, a3) optionally at least one sulfonating agent a4) optionally at least one urea derivative, and a5) optionally at least one further aromatic or heteroaromatic, or a physiologically tolerable salt thereof, with the precondition that the component a1) is not salicylic acid or sulfosalicylic acid if the component a4) is melamine. |