Measurement of tension in molten films can be used to control the quality of film products. It is also critical to the analysis and the modeling of the film casting process. In this work, the film tension of three-layer film consisting of LDPE and LLDPE were measured using a non-contacting air nozzle system. The dependence of film tension on draw ratio and film thickness fraction was related to the rheological properties of the polymer melts. Oscillation of film tension was observed when draw resonance occurred. The frequency of thickness oscillation in the solidified film was found to be similar to that of the tension oscillation in the molten film.
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