Abstract: The invention relates to the use of at least one open-chain, optionally branched, ether isocyanate having an NCO functionality?1, wherein 2 or 3 carbon atoms are present between at least one NCO group and at least one ether-oxygen atom, optionally in the presence of other reactants such as alcohols, amines, water, CO2, or of other reactants having an NCO functionality?1, optionally in the presence of at least one catalyst, to increase the reaction speed and/or to reduce the optionally required catalyst amount during isocyanate modification. The invention further relates to a process for modifying isocyanates, to the modified isocyanates as such and to a two-component system or one-component system and to the moldings, coatings and composite parts obtainable therefrom.