The invention relates to a composition comprising a prepolymer as component (A), wherein the prepolymer comprises aziridino groups and is characterized by an equivalent weight EW1, a crosslinker as component (B), wherein the crosslinker has a structure being different from the structure of the prepolymer and comprises aziridino groups and is characterized by an equivalent weight EW2, an initiator as component (C) being able to start curing of the composition, optionally filler(s) as component (D) and optionally additive(s) as component (E), wherein equivalent weight is defined as (molecular mass of the molecule)/(number of aziridino groups present in the molecule) and wherein EW1>EW2. The invention also relates to the use of the composition for coating, sealing, moulding, adhering, making impressions, producing a dental material.