This procedure determines the AA generated by a resin as a function of time at a given temperature.
Resin is dried to <50 ppm moisture in a vacuum oven at 165°C and loaded into a capillary rheometer that has been equilibrated to a specified temperature. The capillary rheometer temperature is typically 285°C for this test but can be set anywhere between 260°C-290°C in order to match the temperatures that the resin would encounter during injection molding. The resin samples are extruded from the rheometer into cold water after holding for timed intervals of 4 minutes, 6 minutes, 8 minutes, 10 minutes and 12 minutes, (typically a sample of the resin at 0 dwell time is run also in order to determine a dried resin content value). The extrudate is quickly towel and air dried and is then cryogenically ground to a small particle size and analyzed for AA content as described in the AA Content description. The AA generation rate is shown graphically as a function of dwell time.