The production of hard-soft-combinations (e.g. catheter coupler in medical field or rain sensor in automobile industry) via multi injection molding gained more and more importance in the last years. This is attributed to different factors. One principle reason is that the use of two-component injection molding technique has many advantages such as cancelling subsequent and complex steps and shortening the process chain. Furthermore this technique allows the combination of the properties of the single components like the high stiffness of the hard component and the elastic properties of the soft component. Because of the incompatibility of some polymers the adhesion on the interface has to be determined. Thereby adhesion is not only influenced by the applied polymers, but also by the injection molding parameters and the characteristics of the mold. Besides already known combinations of thermoplastics with thermoplastic elastomers (TPE), there consists the possibility to apply liquid silicone rubber (LSR) as soft component. A thermoplastic/LSR combination gains in importance due to the specific advantages of LSR (e.g. good mechanical and thermo-mechanical properties as well as good chemical resistance) to TPE. The firmly adhesion between LSR and thermoplastics is currently one of the key challenges when dealing with those combinations. So it is coercively necessary to improve adhesion between the two components by adding an adhesion promoter. To determine the promoters influence, it is necessary to develop a suitable testing method to investigate e.g. the peal resistance. The current German standard “VDI Richtlinie 2019”, which is actually only employed for thermoplastic/TPE combinations, can serve as a model to determine the adhesion of thermoplastic/LSR combinations. In the standard a geometrically defined sample of hard-soft-combination is mechanically mounted into testing device, where the soft component can be pulled off. The test offers the peal strength and a fracture surface. This paper presents the evaluation of mechanical bonding strength of selected thermoplastic/LSR combinations (e.g. PBT or PA with LSR) characterized on an adapted peal-test device.