Polyisocyanates with improved properties

Abstract

The invention relates to a process for producing modified isocyanates by reacting at least one organic di- and/or triisocyanate in the at least temporary absence of a component A1 comprising at least one tetramethyl ammonium salt and/or at least one cyclic ammonium salt containing a cation of formula (I), wherein: Y is a linear or branched C2-C20 segment which optionally also carries other substituents and is optionally interrupted by heteroatoms from the group including oxygen, sulphur, nitrogen and aromatic rings, and which optionally also carries other rings; and wherein either the substituents R1 and R2 in the N position, independently of each other, are the same or different, substituted or unsubstituted, optionally branched, aliphatic C1-C20 groups, aromatic C6-C20 groups or araliphatic C7-C20 groups; or the substituents R1 and R2 in the N position together form a ring segment X, with the same definition as given above for Y or a different definition; and when a predefinable degree of conversion based on the total amount of NCO groups of the at least one organic di- and/or triisocyanate is reached, stopping the reaction by adding a substoichiometric amount, based on the molar amount of the cation of formula (I) in component A1, of a component A2 comprising at least one acidic compound which has a pKs value less than 4.0 and is other than HF; and, after optional purification, the resulting modified isocyanate is mixed with a component A3 comprising an acidic compound which has a pKs value less than 4.0 and is other than HF, and the at least one acidic compound in components A2 and A3 can be the same or different.

Dependencies are inferred from the claim text.