A process for producing a water-emulsifiable polyisocyanate formulation, in which, in a first process step,
(A) a dispersion-active reaction product (E) is prepared from at least one diisocyanate selected from the group of hexamethylene 1,6-diisocyanate, pentamethylene 1,5-diisocyanate, 4,4′-di(isocyanatocyclohexyl)methane, 1-isocyanato-3,3,5-trimethyl-5-(isocyanatomethyl)cyclohexane, tolylene 2,4- and 2,6-diisocyanate, tetramethylxylylene diisocyanate, p-xylylene diisocyanate, 2,4′- and 4,4′-diisocyanatodiphenylmethane, with at least one mono- or polyhydric polyalkylene ether alcohol having 2 to 4 carbon atoms in the alkylene groups that comprises a polymer chain having at least 8 ethylene oxide units, and the resultant reaction product (E), in a second process step, (B) is mixed with at least one (cyclo)aliphatic polyisocyanate having an average NCO functionality of 2.2 to 5.0, preferably of 2.5 to 4.0, wherein step (B) is performed in the presence of an allophanatization catalyst and the conditions are chosen such that (E) and the polyisocyanate form allophanate groups, characterized in that the allophanatization catalyst is at least one salt consisting of a metal cation and at least one dithiophosphate anion.