A method for curing a chemical composition, the composition containing at least one or more binders having ethylenically unsaturated groups, as well as one or more initiators for triggering a radical polymerization. The method includes a thermal curing step, in which the curing of the composition is effected by a radical polymerization of the binder, which is triggered by a thermal initiator and is carried out under protective gas. Paint films having improved mechanical properties can be produced using the method according to the present invention.