| abstract |
The present invention relates to a process for the preparation of a water-emulsifiable polyisocyanate formulation, wherein in a first process step (A) a dispersed reaction product (E) is prepared from at least one diisocyanate selected from the group consisting of 1,6 - Hexamethylene diisocyanate, 1,5-pentamethylene diisocyanate, 4,4'-bis-(isocyanatocyclohexyl)-methane, 1-isocyanato-3,3,5-trimethyl- 5-(Isocyanatomethyl)cyclohexane, 2,4-toluene diisocyanate and 2,6-toluene diisocyanate, tetramethylxylylene diisocyanate, p-xylylene diisocyanate and 2, 4'-diisocyanatodiphenylmethane and 4,4'-diisocyanatodiphenylmethane; and at least one mono- or polyvalent polyalkylene ether alcohol having 2 to 4 C atoms in the alkylene group and has a polyether chain comprising at least 8 ethylene oxide units, in a second method step (B), the resulting reaction product (E) is combined with at least one average NCO functionality of 2.2-5.0, preferably 2.5-4.0 (Cyclo)aliphatic polyisocyanates are mixed, step (B) is carried out in the presence of an allophanation catalyst, and conditions are chosen such that allophanate groups are formed from (E) and the polyisocyanate, characterized by urea The formate esterification catalyst is composed of at least one salt consisting of a metal cation and at least one dithiophosphate anion. |