Thermal Stability

Purpose

The Thermal Stability Test is designed to insure that dimensional changes in carbonated PET bottles will not be excessive during their expected lifetime. This is also known as a “creep” test.

Description

Representative bottles are measured under “as-received” non-carbonated conditions. Bottles are then carbonated and placed in an environmental room at 37.8°C ± 2.5° (100°F ± 5°) and 85% ± 10% humidity for 24 hours. After this time, bottles are removed from the room and re-measured (final measurements). These final measurements must be completed within 4 hours of removal from the environmental chamber and must be made at the same locations as the initial measurements. A comparison is then made between the “as-received” and the final measurements.