Urea-modified carbodiimides of formula (I) are claimed: (R)m-N(H)2-m-(O)C-NH-ZN=C=N-Zn-NH-(O)C-N(H)2-m-(R)m (I) R = 1-12 C alkyl or 3-10 C cycloalkyl; Z = 1-12 C alkylene, 3-10C cycloalkylene, 4-16 C alkylene with a cyclic or acyclic structure, or 8-16 C alkylene with an aromatic ring; n = 1-50; m = 1 or 2. Also claimed is a process for the prodn. of (I) by reacting an aliphatic diisocyanate of formula OCN-Z-NCO (II) with a prim. or sec. amine (III) and carbodiimidising the prod. in presence of a suitable catalyst (IV), or by carbodiimidising (II) and reacting the carbodiimide with (III).
