An innovative process for packaging films sealing has been recently promoted: Heat is provided on the upper side of the polymer films. In this paper, sealing conditions are studied for two PET-PE films. Melting temperature of the sealant layer material was determined by differential scanning calorimetry (DSC), through both conventional and successive self nucleation and annealing procedures. Interface temperature was measured during sealing, and a temperature model was fitted to compute the effective sealing time for each process parameter. Unconventional T-peel tests were established with disk-shaped seal samples. Strengths of the seals formed for different process parameters were measured. Results have shown that the melting temperature measured by DSC (108 C and 99 C for PE70 and PE120, respectively) is the seal initiation temperature of the materials. Results of T-peel tests can be divided in two regions: A growth region where seal strength values increase, up to a threshold at which the seal strength is almost constant (20 N/10 mm). In the growth region, we propose a time-temperature relationship between seal strength, tool temperature, and effective sealing time in the form of an Arrhenius model C exp α T

In this paper, we present an innovative welding process for packaging applications developed by SEALESTER Company. For polymer films, studies have revealed that the welding interface must reach a specific temperature, known as “sealing initiation temperature”, to obtain a sealed joint. In this paper, we will be studying the effect of the process parameters on the evolution of temperature at the welding interface. For this purpose, thermocouples have been placed between the films at different points of the trajectory to measure the temperature evolution. Process parameters and temperature measurements were recorded in each experiment. Results show that the most influential parameters are the temperature and the linear velocity of the tool. Rotational frequency affects the heat distribution on the sealing surface. A minimum pressure must be applied. In conclusion, this new process can produce sealed polymer packages. Future work will consist of studying the quality of obtained seal in addition to optimization and control of the process.

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