Abstract
Crystallized polyethylene terephthalate (CPET) is nearly transparent to microwave energy and can sustain 200°C convection oven temperatures for more than 60 min. without embrittling. As a result, it is a leading candidate for thermo formed freezer-to-oven portion servings. The rate of crystallization is controlled by adding small amounts of organic and/or inorganic nucleants. Nearly amorphous sheet of thickness of 60 mil or less can be extruded by casting onto chill rolls. This sheet is then rapidly heated to forming temperature with radiant and/or convection energy sources. The rapidly crystallizing sheet is finally formed against a heated mold. This paper proposes a way of understanding the time-dependent nature of CPET crystal linity during the typical thermoforming process. The results are compared with the patent literature.
Get full access to this article
View all access options for this article.