Date of Award

12-2014

Document Type

Thesis

Degree Name

Master of Science (MS)

Legacy Department

Packaging Science

Advisor

Darby, Duncan O

Committee Member

Whiteside , William S

Committee Member

Rieck , James R

Abstract

This research determines if there is any relationship between the peel force, the opening force and the burst force for a semi-rigid cup and lid system, for pre- and post-retort conditions. It also compares the relationship (regression lines) between these forces pre- and post-retort. These seal results were studied by varying the sealing parameters of dwell time and temperature while keeping the pressure constant. Polypropylene cups and a peelable barrier retort lidding were used in this study. As compared to past research, a different peel testing technique was used to measure the peel and the opening force. The entire lid was peeled to measure the 'true' opening and peel forces experienced by the consumer. A dynamic burst test was performed using unrestrained plates. Creep tests were performed to ensure a good quality of seals. The relationship for these forces, which were measured on different cups due to their destructive nature, were found using instrument variables (dwell time and temperature). The study found that there was a relationship between these the three force for both pre- and post-retort conditions. Six regression equations for these relationships were found. The pre- and post-retort regression lines were compared. The nature of these forces were found to be different pre- and post-retort. Different concepts were discussed to better understand the nature of these forces pre- and post-retort, such as modes of failure, cold crystallization of materials in the retort, sealant flow at high temperatures and dwell times, and so on.

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