| abstract |
The invention relates to a mixture comprisingn i) at least one condensation product (A) obtainable by reaction ofn a1) at least one aromatic system or heteroaromatic system, a2) at least one carbonyl compound, a3) if appropriate at least one sulfonating agent and a4) if appropriate at least one urea derivative,n nwhere the condensation product (A) has an M w value ≧9000 g/mol, andn n ii) at least one tanning agent having an M w value ≦3000 g/mol. |