摘要 |
The instant invention is directed to a process for the preparation of modified polyisocyanates which contain sulfonic acid alkyl ester groups and in which the isocyanate groups may be at least partly in the dimerized form, comprising: reacting isocyanatoaryl sulfonic acids having at least two isocyanate groups and wherein the isocyanate groups may be at least partly in the dimerized form, optionally as mixtures with mono and/or polyisocyanates which are free from sulfonic acid groups, with di- and/or tetrahydrofurans at 0 DEG to 190 DEG C., wherein the equivalent ratio of isocyanate groups, including any isocyanate groups present in the dimerized form, to sulfonic acid groups is greater than 1 and the equivalent ratio of di- and tetrahydrofuran groups to sulfonic acid groups is from 0.1:1 to 10:1.
|