Process for the production of modified polyisocyanates, the polyisocyanates obtainable by this process and their use as binders or as a binder component

Abstract

The present invention is directed to a process for the production of urethane- or isocyanurate-modified polyisocyanates based on a starting diisocyanate selected from (i) 2,4-diisocyanatotoluene or mixtures thereof with up to about 35%, based on the mixture, of 2,6-diisocyanatotoluene, (ii) mixtures of the diisocyanates mentioned under (i) with up to 80 NCO equivalent %, based on the mixture, of 1,6-diisocyanatohexane and (iii) 1-isocyanato-3,3,5-trimethyl-5-isocyanatomethyl cyclohexane by reacting the starting diisocyanate with substoichiometric quantities of polyhydric alcohols or trimerizing a portion of the isocyanate groups of the starting diisocyanate, removing sufficient excess, unreacted starting diisocyanate to obtain modified polyisocyanates containing at most 3% by weight, based on solids, of monomeric starting diisocyanate, characterized in that, the content of starting diisocyanate is further reduced by adding at least 10 mol-% water, based on the content of unreacted 2,4-diisocyanatotoluene or 1-isocyanato-3,3,5-trimethyl-5-isocyanatomethyl cyclohexane present, to the modified polyisocyanates. The present invention is also directed to the low-monomer polyisocyanates obtained by this process and their use as the binder component in one-component or two-component polyurethane lacquers.

Dependencies are inferred from the claim text.