The subject matter is a new composition comprising at least one hydroxyl-group containing resin, at least one nitroso-containing compound or at least one nitroso precursor compound, at least one blocked isocyanate and at least one crystallization germ suitable as primer or coating for rubber to substrate bonding, which provides a scratch resistant surface, when applied, and excellent adhesion and steam resistance for rubber to substrate bonds. These compositions can especially be used as one coat systems.