| abstract |
The invention provides crystalline polyester articles having an oxygen permeability of from about 0.2 to about 4.9 cc-mil/100 in2-24 hr-atm, and an enthalpy of recrystallization of from about 0 to about -2.1 cal/g. They are prepared by: a) heating a crystallizable polyester above the temperature of its peak rate of crystallization from melt, b) shaping it at or above this crystallization temperature in a heated form and c) cooling it at a rate of about 5 °C to 80 °C per minute. The polyester articles are useful as containers for microwavable, ovenable and/or frozen foods. They have good gas barrier properties, and post-mold dimensional sta bility from about -60 °C to about 200 °C. |