VULCANIZATION OF UNSATURATED RUBBERS WITH VULCANIZING ANTIOXIDANTS AND THEIR HEAT AGING RESISTANCE

Abstract

Evaluation of 2-antioxidant group-4, 6-bis(4-morphorinyl trithio)1, 3, 5-triazine(Vulcanizing antioxidant) on unsaturated rubbers such as IR, BR, SBR, and EPDM has been investigated for vulcanizing properties, the % bound of antioxidant groups, the structure of crosslinkage, and the heat resistance of vulcanizates. Vulcanizing antioxidants acted as a vulcanizing agent in the copresence of ZnO and stearic acid. The vulcanizing reactivity was influenced by the kind of rubbers. The copresence of accelerators such as TMTM, CBS, and MBTS was very effective to increase vulcanizating rates and crosslinking degree. The % bound of antioxidant groups was large for BR and SBR, but small for IR and EPDM. Both CBS and MBTS were effective accelerators to increase the % bound, and TMTM was effective one to increase the monosulfide crosslinkage contents. The combination of vulcanizing antioxidant and TMTM was found to give the vulcanizates which are effective under the conditons that contact with high temperature and solvents, in which commercial antioxidants commonly are removed, as they have both excellent % bound and monosulfide crosslinkage contents.