English Abstract

Variation of the States of Rubber
6. Field Aging of Tire Parts and Durability

Asahiro AHAGON
Retired from Yokohama Rubber Co., Ltd.
Nippon Gomu Kyokaishi,(2017),90(2),41-46 General Review in Japanese

Belt separation, the final stage of belt edge crack growth, is discussed to illustrate the influence of tire aging to durability. The resistance to crack propagation of aged rubbers correlates well with extension ratio at break λb, which is considered to represent the extent of crosslinking due to oxidative aging. Resistance to crack propagation falls with decreasing λb, i. e., with crosslinking during aging. Consequently, aging of tire causes deterioration of resistance to belt separation.
Reduced oxygen permeation through tire wall, by means of nitrogen inflation and use of halogenated butyl rubber for inner liner, leads to better durability. It is also found that lower temperature mixing leads to better aging resistance and tire durability.

Keywords: Tire Aging, Durability, Belt Separation, Edge Separation, Crack Growth.