| 摘要 |
An open cell foam with thermal memory characteristic is used as an indicator for heat damage to an article containing heat sensitive contents packaged in a carton. The foam material may be a polyurethane-based thermoplastic polymer referred to as "Cold Hibernated Elastic Memory" (CHEM) foam. The thermal memory foam can be produced in compressed form and used as inserts in the carton. Upon exposure to a temperature at or above the foam glass transition temperature, the foam insert expands to substantially its original shape (volume) so as to apply a compressive force against the article, making it difficult to remove from the carton. Alternatively, the expanded foam will deform the carton walls, providing an external indication of heat damage. The foam can also be used as a heat-indicating element in an inspection panel of the carton, which ruptures so as to provide external indication of heat damage.
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