Abstract: Polyfunctional polyisocyanate polyadducts are prepared by a process comprising (i) preparation of an adduct by reacting (a) an at least trifunctional component (a1) reactive with isocyanate groups or a difunctional component (a2) reactive with isocyanate groups or a mixture of the components (a1) and (a2) with (b) a di- or polyisocyanate, the reaction ratio being chosen so that on average the polyadduct (A) contains one isocyanate group and more than one group reactive with isocyanate groups, (ii) if required, intermolecular addition reaction of the adduct (A) to give a polyadduct (P) which contains on average one isocyanate group and more than two groups reactive with isocyanate groups, and (iii) reaction of the adduct (A) or of the polyadduct (P) with an at least difunctional component (c) reactive with isocyanate groups.

Abstract: Polyfunctional polyisocyanate polyadducts are prepared by a process comprising

Abstract: In a process for preparing dendritic or highly branched polyurethanes by reacting diisocyanates and/or polyisocyanates with compounds containing at least two groups which are reactive toward isocyanates, at least one of the reactants contains functional groups having a different reactivity compared to the other reactant and the reaction conditions are selected so that only certain reactive groups react with one another in each reaction step.

Abstract: Polyisocyanates containing isocyanurate groups are prepared by a partial trimerization of (cyclo)aliphatic diisocyanates in the presence of at least one trimerization catalyst selected from the group consisting of tetraalkylammonium alkyl carbonates of the formula (I) ##STR1## (quaternary ammonioalkyl) carbonates having a betaine structure of the formula (II) ##STR2## and the preferred use of the polyisocyanates containing isocyanurate groups which are obtainable in this way is aspolyisocyanate component in polyurethane finishes.