Effect of Liquid Contamination on Hermeticity and Seal Strength of Flexible Pouches with LLDPE

Flexible packaging is a growing successful market and the majority of flexible package applications are for the food industry. The demand for process optimization and reduced production costs, has led to an increase in flexible packaging. However, fast production lines can result in contamination in the seal area. For flexible food packaging, contamination is considered any food particle or substance trapped in the seal area. Current quality control processes can detect contamination in the seal area, but it is not determined if seal contamination affects seal quality. Oil-based and sodium based snack foods are two common categories that can be packaged on a horizontal form fill and seal (HFFS) flow-wrap machine. The study uses vegetable oil and a salt water solution to simulate the effect of liquid contamination along the T-point of flexible pouches made on an HFFS. The T-point refers to where the fin seal meets the end seal and requires the seal jaw to seal through four layers of film, which is the most difficult point to seal. The study tests a combination of different sealing temperatures and dwell time to determine the optimal sealing condition for a hermetic seal. A quality hermetic seal provides an enclosed seal with no leaks due to successful polymer chain entanglement between the two sealant layers. The different test categories of the study are non-contaminated (control), salt water solution for salt based foods, and vegetable oil for oil-based foods. Given the test parameters of the study, 140⁰C sealing temperature and 0.3 seconds dwell time are considered to be the optimal sealing condition for all three test categories. For Phase 1 of the study, salt water had a lower Hermeticity pass rate compared to vegetable oil and non-contaminated seals. In addition, the effect of refrigerated storage temperature and ambient storage temperature did not show to be significant for any of the test categories. However, refrigerated conditions showed a higher Hermeticity pass rate, but it was not statistically different. The findings for seal strength indicated no test category had higher or lower seal strength over the 14 day test period. Overall, the study shows there is no effect of liquid contaminant on Hermeticity and seal strength for flexible film with LLDPE sealant layer