Squeeze flow in multilayer polymeric films: Effect of material characteristics and process conditions

In this work, effects of sealing temperature, time, pressure, as well as sealant thickness and viscosity on squeeze out flow (SOF) in heat sealing were examined. A new image analysis approach is presented to quantify SOF in heat sealing. It was found that increasing temperature or pressure could improve SOF but only in thick 130 mu m sealants and reducing the sealant thickness to 50 mu m suppressed SOF. Reducing viscosity in 50 mu m sealant films was also found to improve SOF only at high-sealing pressure and long sealing times. Three approaches were used to model SOF: analytical one-dimensional model, numerical one-dimensional model using finite difference method (FDM), (iii) Numerical two-dimensional model using finite element analysis. Heat transfer was modeled, and it was shown that heat transfer induces a delay in SOF. When the FDM and the heat transfer models were combined, a good agreement between experimental and model prediction could be obtained. In addition, modeling results showed that SOF occurred in shear rates within the transition region between the Newtonian and Power-law regions. This indicates the importance of considering the Carreau-Yasuda fluid behavior in modeling of SOF.

Automated summary

The study examined the effects of sealing temperature and pressure on the squeeze out flow in heat sealing, with additional consideration of sealant thickness and viscosity. Three models were used to analyze the behavior of squeeze out flow, highlighting the importance of Carreau-Yasuda fluid behavior in modeling. The combination of finite difference method and heat transfer models showed good agreement between experimental and predicted results.