A curable composition comprising

(A) constituents containing carbamate groups I:

—O—C(O)—NHR  (I)

• in which R=a hydrogen atom or an alkyl, cycloalkyl or aryl group,

(B) constituents containing carbamate-reactive groups, the equivalents ratio of carbamate-reactive groups in

(B) to carbamate groups in (A) being 0.2,

(C) adducts preparable from

• (c1) polyisocyanates and
• (c2) compounds II containing isocyanate-reactive functional groups: ##STR1##
  • in which
  • R¹ and R²: independently of one another are hydrogen atoms or alkyl radicals;
  • X and Y: oxygen atom, sulfur atom or a radical N—R⁶, in which R⁶=aliphatic radical;
  • R³: is an alkylene radical;
  • R⁴ and R⁵: are hydrogen atoms, isocyanate-reactive functional groups or R⁶;
  • with the proviso that one group R⁴, R⁵ or R⁶ contains an isocyanate-reactive functional group or R⁴ or R⁵ is an isocyanate-reactive functional group and the other radicals R⁴, R⁵ or R⁶—where present—contain no isocyanate-reactive groups;
  • the molar ratio of (c1) to (c2) being chosen such that the adducts (C) contain in the molecule isocyanate groups; process for its preparation, and its use.