Since the number of the vulcanizate network obtained by the ordinary sulfur vulcanization system is a polysulfide crosslink, the crosslinking efficiency of sulfur in the vulcanization reaction is low. Experiments have shown that changing the proportion of accelerator can effectively improve the crosslinking efficiency of sulfur in the vulcanization reaction and improve the structure and product properties of vulcanizate in rubber manufacture.

When the ratio of accelerator to vulcanizing agent rises, the network structure of vulcanizate changes, the content of monosulfide crosslinks increases, and the degree of effective cross-linking of sulfur increases, but the fatigue life first rises and then decreases to increase sulfur during vulcanization. Crosslinking efficiency, there are two commonly used methods of coordination.

(1) High-promoting, low-sulfur blending to increase the amount of accelerator (3~5 parts) and reduce the amount of sulfur (0.3~0.5 parts).

(2) Sulfur-free coordination is the combination of sulfur carrier, such as TMTD or DTDM (1.5~2 parts).

In the vulcanized rubber network obtained by the above two combinations, the content of single bond and double bond accounts for more than 90%, and the network has little main chain modification. The utilization rate of sulfur in the vulcanization system is high, and it is called effective vulcanization system (EV). The vulcanizate of O EV vulcanization system has high resistance to thermal aging, but the initial dynamic fatigue performance is poor. Commonly used in high temperature static products such as sealing products, high temperature rapid vulcanization system.