In our research, we investigated the chemical foaming of mixed plastic waste granulate (VMHD) using a combination of endothermic and exothermic foaming agents. We found that increasing the exothermic foaming agent improved cell distribution but reduced flexibility and impact resistance. The highest porosity (30.04%) was achieved with 0.5% endothermic and 3.5% exothermic foaming agents. Our results indicate that the proper ratio of foaming agents is crucial for optimizing the mechanical properties of the material.