Aqueous polyurethane-polyurea dispersion having polyurethane-polyurea particles present in the dispersion, having an average particle size of 40 to 2000 nm (measurement method: see Description), and having a gel fraction of at least 50 (measurement method: see Description), obtainable by preparing a composition comprising, based in each case on the total amount of the composition, (Z.1) 15 to 65 wt% of at least one intermediate containing isocyanate groups and having blocked primary amino groups, its preparation comprising the reaction (Z.1.1) of at least one polyurethane prepolymer containing isocyanate groups and comprising anionic groups and/or groups which can be converted into anionic groups, with (Z.1.2) at least one polyamine comprising at least two blocked primary amino groups and at least one free secondary amino group, by addition reaction of isocyanate groups from (Z.1.1) with free secondary amino groups from (Z.1.2), (Z.2) 35 to 85 wt% of at least one organic solvent which possesses a solubility in water of not more than 38 wt% at a temperature of 20°C (measurement method: see Description), dispersing the composition in aqueous phase, and at least partly removing the at least one organic solvent (Z.2) from the dispersion obtained in. preparing a composition comprising, based in each case on the total amount of the composition, (Z.1) 15 to 65 wt% of at least one intermediate containing isocyanate groups and having blocked primary amino groups, its preparation comprising the reaction (Z.1.1) of at least one polyurethane prepolymer containing isocyanate groups and comprising anionic groups and/or groups which can be converted into anionic groups, with (Z.1.2) at least one polyamine comprising at least two blocked primary amino groups and at least one free secondary amino group, by addition reaction of isocyanate groups from (Z.1.1) with free secondary amino groups from (Z.1.2), (Z.2) 35 to 85 wt% of at least one organic solvent which possesses a solubility in water of not more than 38 wt% at a temperature of 20°C (measurement method: see Description), (Z.1) 15 to 65 wt% of at least one intermediate containing isocyanate groups and having blocked primary amino groups, its preparation comprising the reaction (Z.1.1) of at least one polyurethane prepolymer containing isocyanate groups and comprising anionic groups and/or groups which can be converted into anionic groups, with (Z.1.2) at least one polyamine comprising at least two blocked primary amino groups and at least one free secondary amino group, by addition reaction of isocyanate groups from (Z.1.1) with free secondary amino groups from (Z.1.2), (Z.1.1) of at least one polyurethane prepolymer containing isocyanate groups and comprising anionic groups and/or groups which can be converted into anionic groups, with (Z.1.2) at least one polyamine comprising at least two blocked primary amino groups and at least one free secondary amino group, by addition reaction of isocyanate groups from (Z.1.1) with free secondary amino groups from (Z.1.2), (Z.2) 35 to 85 wt% of at least one organic solvent which possesses a solubility in water of not more than 38 wt% at a temperature of 20°C (measurement method: see Description), dispersing the composition in aqueous phase, and at least partly removing the at least one organic solvent (Z.2) from the dispersion obtained in.