The purpose of this study was to clarify the relation between the cooling condition after heat sealing and the variation of heat seal strength before and after the sterilization treatment for coextruded multilayered polyethylene (PE) film. The PE film consisting of high density polyethylene and linear low density polyethylene was prepared by water-cooled tubular film blowing process. Heat sealing process consisted of two steps, i.e. heating and cooling processes. Crystallization behavior of each component in the cooling process of multilayered PE film was analyzed detecting the exothermic heat of crystallization through the measurement of the interface temperature. Under the condition of rapid cooling using cooling bars of 20°C, the highest heat seal strength was obtained while the largest reduction of heat seal strength after the sterilization treatment was also observed. On the other hand, the samples of slow cooling conditions showed higher seal strengthafterthesterilizationincomparisonwiththatoftherapidcool ing condition because of smaller degree of strength reduction. From the view points of high productivity and good appearance of sealed portion without distortion, however, incorporation of cooling process is indispensable. Accordingly, among the four different cooling conditions examined in this research, application of cooling bars of 80°C was concluded to be the optimum condition for the peelable heat sealing of the multilayered PE films.

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