Improving the heat stability of sulfur crosslinked diene rubber vulcanizates is a challenge for every compounder during the developing of new rubber articles. A broad spectrum of different mechanical and dynamic properties could be achieved by varying the amount of sulfur and the accelerator type. To avoid reversion or improve the heat stability, different concepts have been evaluated within the last 30 to 40 years or are in use: 1. Slow postcuring 2. Repair of network 3. Special crosslinker 4. Stable crosslinks By using such kind of products, advantages in mechanical and dynamic properties could be achieved in comparison with conventional or semi-efficient crosslinking systems.