In the recent global environment, the ozone in the atmosphere near the surface of the earth is increasing due to the expansion of the ozone hole, the increase in the amount of ultraviolet rays, and the increase in NOx.
Damage of vulcanized rubber suffered by ozone is quite large. Therefore, design of rubber formulation is necessary, such as increase of wax content and selection of HNBR with high conversion of hydrogenation, even though conventional vulcanized rubber with ozone resistance.