INFLUENCE OF PROCESSING CONDITIONS ON THE PEEL BEHAVIOR OF POLYETHYLENE/ POLYBUTENE-1 PEEL SYSTEMS

ABSTRACT: The specific peel system low-density polyethylene/isotactic poly-butene-1 (PE-LD/iPB-1), which is often used for protective packages, was investi-gated in this study. The required peel force to open the package depends on the content of iPB-1 and on the processing conditions of the blowing process. Commer-cial products have a constant amount of iPB-1. Thus, a defined peel force can be adjusted by varying the processing conditions. The standard peel system PE-LD with 6wt % iPB-1 was investigated in dependence on the processing conditions. The most important processing parameters of the processing line (extruder, die head, tube forming area) were varied and their influence on the peel properties was examined. For example the temperatures of the melt within the extruder, the size of the die gap within the die head, and the cooling behavior of the film bubble were investigated. Higher melt temperatures within the extruder decreased the peel force. The investigations also revealed a strong dependence of the peel force on the size of the die gap and on the degree of cooling. The new developed parameter time of solidification was used to characterize the cooling behavior. KEY WORDS: polyethylene/polybutene-1 films, blowing process, processing conditions, peel test, peel force