PREPARATION OF POLYISOCYANATES CONTAINING URETDIONE GROUPS USING PHOSPHINE CATALYSTS

摘要

The invention provides a process for isocyanate dimerization (uretdione formation) and a process for preparing polyisocyanates having a high content of uretdione groups, using specific phosphines as catalysts. The phosphines have one or two tertiary alkyl radicals bound directly to phosphorus.