Patent ID: 6936677

Claim:
A method for promoting the reaction of closing uretidione rings or of opening uretidione rings and their reaction with a nucleophilic compound having a mobile hydrogen atom, said method of closing uretdione rings comprising cyclodimerizing an aliphatic or cycloaliphatic isocyanate in the present of a nitrogenous heterocyclic compound having at least five ring members and at least two ring nitrogen atoms to form a uretidione dimer, and said method of opening uretidione rings comprising reacting a compound containing at least one uretidione ring derived from an aliphatic or cycloaliphatic isocyanate with a nucleophilic compound having a mobile hydrogen atom in the presence of a mtrogenous heterocyclic compound having at least five ring members and at least two ring nitrogen atoms, with the proviso that, when the nitrogenous heterocyclic compound is imidazole, the opening/closing reaction is not the reaction of closing isocyanate compounds to uretidione rings in the presence of a quatemary ammonium salt.