An adhesive for adhering synthetic and/or metal substrates, selected from liquid or thermoplastic adhesives which have urethane groups in the polymer chain is provided, wherein the adhesive is selected from NCO-reactive adhesives, silane-reactive adhesives or thermoplastic polyurethanes (TPU) and include as a constituent 0.01-10 wt% of at least one compound (H) having a molecular weight of less than 500 g/mol, and the compound has at least one sulphonamide group having an SO2-NH-C(O) structure or at least one amidosulphonate group.