English Abstract
Degradation and Trouble Countermeasure of Vulcanized Rubber Products
(Degradation by Residual Chlorine in City Water and Copper-induced Degradation and Ozone Degradation by Influence of Environmental Deterioration in the Earth)

Yoshito OHTAKE
Chemicals Evaluation and Research Insitute, Japan, Sugito-machi, Kitakatsushika-gun, Saitama, Japan
Nippon Gomu Kyokaishi,(2006),79(11),529-536 General Review in Japanese

The degradation behavior of EPDM by chlorine in water was reviewed. In the low concentration chlorine water such as city water, the degradation process was expected to be a lowering of EPDM molecular weight causing the softening. In the case of high chlorine concentration, on the other hand, reaction with chlorine increased the cross-linking density leading to hardening of EPDM. In addition, metal ion such as copper ion accelerates the chlorine degradation of EPDM. The ozone concentration in the near ground atmosphere gradually increasing in recent 20 years because of the increasing nitrogen oxides exhausted from automobile and the strong short-wave UV light. We should consider measures against the ozone degradation of the rubber products at once.

Chlorine, EPDM, Ozone, Ultraviolet, City Water