Photostabilization activities of various types of antidegradants for EPDM sulfur vulcanizates with white filler have been evaluated by means of outdoor exposure rack in Miyako-jima and Sun Follow Weather Meter in Tokyo. Notable results are shown below.; (1) The mechanical properties of EPDM vulcanizates without antidegradant changed extremely when exposed in outdoor. Compared to the exposure test by outdoor exposure rack in Miyako-jima, Sun Follow Weather Meter in Tokyo gave an acceleration of approximately 2 to 3 times in the change of physical properties including elongation at break, modulus at 100% and hardness. (2) The outdoor exposure test of EPDM vulcanizates with antidegradants indicates that AA-1, PA-2 and PD-1, especially PD-1 in the test of Sun Follow Weather Meter, exhibited superior photostabilization activity. (3) The analytical data of the antidegradant contents in EPDM vulcanizate showed that the uv adsorbers show higher retention of their contents even after outdoor exposure test, although other antidegradants decreased during ageing because of the chemical reaction concerning photostabilization performance.
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