Radiation-curing binders and a process for their preparation

摘要

The invention relates to a process for preparing binders which contain 1) allophanate groups, 2) groups that react with ethylenically unsaturated compounds with polymerization on exposure to actinic radiation (radiation-curing groups) and 3) optionally NCO-reactive groups, by reacting at temperatures ≦130° C.
A) one or more NCO-functional compounds containing uretdione groups withB) one or more compounds that contain isocyanate-reactive groups and groups that react with ethylenically unsaturated compounds with polymerization on exposure to actinic radiation (radiation-curing groups), and thenC) with one or more saturated, hydroxyl-containing compounds other than B), at least one of these compounds having an OH functionality of ≧2, in the presence ofD) a catalyst containing one or more zinc compounds,

the reaction with compounds C) taking place at least proportionally with the formation of allophanate groups.
;The present invention also relates to the binders obtained by the process of the invention.

主权项

1. A process for preparing a binder containing allophanate groups comprising the steps of
1) reacting A) one or more NCO-functional compounds containing uretdione groups with B) one or more compounds that contain isocyanate-reactive groups, uretdione-reactive groups, and contain groups that react with ethylenically unsaturated compounds with polymerization on exposure to actinic radiation , and 2) performing a uretdione ring-opening reaction between the product of step 1 with C) one or more saturated, hydroxyl-containing compounds other than B), at least one of these compounds having an OH functionality of ≧2, in the presence of D) a catalyst containing one or more zinc compounds, wherein the process is performed at temperatures of from 20 to 100° C. and wherein the sum of NCO groups and uretdione groups of A exceeds the sum of NCO-reactive groups and uretdione-reactive groups present in B.