In peel, tests between polycarbonate/polyethersulfone (PC/PES) blends with different compositions and thermoplastic polyurethane (TPU) films with different thicknesses a large decrease in energy release rate (Figure presented.) is observed when the PC/PES blends formed a co-continuous structure. With SEM analysis, XRD measurements, selective PC etching of failed samples, and finite element modeling of the stress distributions in the co-continuous region this fracture behavior can be explained. It is caused by the interplay between the formation of the main crack in the process zone and the size and density of microcracks in the energy dissipation zone. While the pure components PC and PES exhibit good adhesion to the TPU, the immiscibility of PC and PES causes the steady decrease of (Figure presented.) with increasing volume fraction of the minor phase.