A reactive composition contains A) an aqueous polyurethane-polyurea dispersion containing an uretdione group and having an internal emulsifier, the emulsifier having at least one ionogenic group which, in the case of an acidic ionogenic group, has a pKa in water of >8 at room temperature or, in the case of a basic ionogenic group, has a pKb of >8 at room temperature, B) at least one diamine and/or polyamine, wherein a ratio of a latent NCO group in the polyurethane-polyurea dispersion A) containing an uretdione group to the amine groups in component B) is from 4:1 to 1:1, and C) optionally, at least one member selected from the group consisting of an auxiliary, an adjuvant and a catalyst.