English Abstract

Ozone Resistance of Wax Adhered after Bled onto Surface of Vulcanized Rubber

Yuka IWASE *1 *2
Toru SHINDO *1
Hiroaki KONDO *1
Yoshito OHTAKE *1
Seiichi KAWAHARA *2
*1:Chemicals Evaluation and Research Institute, Japan, Kitakatsusika-gun, Saitama, Japan
*2:Nagaoka University of Technology, Nagaoka-shi, Niigata, Japan
Nippon Gomu Kyokaishi,(2017),90(10),463-469 Original Paper in Japanese

Effect of wax on ozone degradation of vulcanized rubber was investigated at temperatures between -30 and 40 . The vulcanized rubber was prepared by mixing synthetic isoprene rubber with CB, sulfur, ZnO, stearic acid, accelerator and wax, followed by heating at 160 for 8 min. It was further heated at 23 , 40 and melting temperature of each wax for 72 hours under 20% stretching, in order to segregate the wax onto the surface of the vulcanized rubber as a bleeding. Ozone exposure tests of the vulcanized rubber were carried out at the temperatures between -30 and 40 in the presence of 50 pphm ozone for 24 and 168 hours, respectively. Crack propagation of the ozone-degraded rubber was observed with a digital microscope. The wax, bleeding onto the surface of the vulcanized rubber, was found to improve the ozone resistance of the rubber as compared with an ordinary bloomed wax.

Keywords: Ozone Degradation, Bloom, Bleed, Paraffin Wax, Microcrystalline Wax, Molecular Weight, Melting Point, Molecular Mobility