The aim of this study is to investigate the influence of additives in thermoplastics on the peel force between liquid silicone rubber (LSR) and thermoplastics. For this purpose, polyamide 6 (PA 6) and polybutylene terephthalate (PBT) are compounded with additives in the first step. In the next step, two-component parts made of LSR and the thermoplastics are injection molded to determine the peel force. In addition, the Mold Flow Index (MFI) is examined to determine the influence of the flow properties on the peel force and Differential Scanning Calorimetry (DSC) analyses are carried out to determine the crystallinity. The more similar the molecular structure of the additive, the lower the influence on the peel force.