Tyre curing bladders are usually prepared by using butyl/neoprene based compounds. To demonstrate the heat resistance and to extend the service life of a bladder, the mechanical properties of butyl/neoprene/ethylene-propylene-diene rubber (EPDM) based compounds in different compositions were analyzed and compared. In this study, the effects of partial replacements of IIR with different types of EPDM in different proportions were studied. Rheological and mechanical properties of vulcanizates were measured before and after the thermal ageing. Curing characteristics of unvulcanized compounds and mechanical properties, permanent set, fatigue index, and IRHD hardness of vulcanized compounds were measured. The better results were obtained by using the recipes containing Keltan 27 type EPDM of 10-20 phr. Mechanical properties of recipes decreased due to high EPDM ratio in the recipes studied. The service life of tyre curing bladders can be increased by the replacement of EPDM with butyl rubber in appropriate type and quantity. (c) 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 557-563, 2007