A mixture of water-emulsifiable isocyanates is described. The mixture contains (A) at least one polyisocyanate (a), (B) at least one emulsifier obtained by reacting at least one polyisocyanate with at least one polyether alcohol having a molecular weight of less than 400 g/mol, (C) at least one emulsifier obtained by reacting at least one polyisocyanate with at least one polyether alcohol having a molecular weight of greater than 450 g/mol, and (D) optionally at least one emulsifier obtained by reacting a polyisocyanate with at least one compound (d) having at least one hydrophilic, non-isocyanate-reactive group and precisely one isocyanate-reactive group (group D2). The weight ratio of component (B) to component (C) in the mixture is from 30:70 to 70:30, preferably from 40:60 to 60:40.