The ultrasonic sealing (USS) is a new and modern possibility to seal peel films for packaging, for example for food and for medical packages. The heat conductive sealing (HCS) in contrast is already well described in science and practice. This study is a comparison of the effectiveness of both the USS and the HCS method using low-density polyethylene/isotactic polybutene-1 peel films. The influence of the recipe of the film, i.e., the amount of the peel component used and the thickness of the peel layer, as well as the sealing parameters, i.e., the sealing temperature, time, and pressure in case of HCS and the sealing force, time, and amplitude in case of USS, on the peel behavior were investigated. To characterize the peel behavior, the peel force, the maximum peel force, and the fracture mechanics, energy release rate were used. The sealing force has a strong impact on the peel properties. This behavior is similar to the influence of the sealing temperature. The peel behavior can be adjusted by varying the content of isotactic polybutene-1.