In technical products, e.g. of the automotive sector, the use of a glass fiber reinforced thermoplastic like PA and crosslinked elastomers such as EPDM or NR is an common chosen hard-soft material combination. The general incompatibility of these polymers prevents good adhesion. In industrial processes a thermally-mechanically stable adhesion is nowadays nearly always achieved by the use of adhesion promoters. The industry is striving to replace this conventional method with new materials which can be processed directly and are more effective, due to the avoidance of solvents and better process robustness. In this investigation a modified PA6 is used, that makes direct bonding between the thermoplastic polymer and the sulfur cured rubber possible. One of the main goals in this study is the definition of the most influencing factors for good adhesion between the polymers used. In a first step the influence of process parameters is investigated by practical tests. For this purpose a variation according to a DoE cube model is performed. The adhesion between the polyamide and the elastomer as well as the resulting fracture pattern is examined by a peeling test. On the assumption that co-vulcanization takes place or interpenetrating polymer networks arise in the boundary layer, it is of great importance to have accurate knowledge about the time dependent temperature development and crosslinking reaction, especially in the interface. Exact knowledge about this can be gained with the aid of simulations. The results from the simulation studies are correlated with the adhesion values from the practical tests.