Property Requirements of Un-vulcanized Rubber

This depends on the polymer type and increases with higher dry filler loading and reduces with peptizing agents, plasticizers, softeners, reclaimed rubber or resins. 

This generally depends on the type and amount of accelerator. The higher the accelerator the faster is the scorch. It can be made slow by the addition of retarders. Increasing softeners often slows down the onset of cure while at the same time improving internal lubrication in the compound. The higher the un-saturation in the rubber the faster is the scorch. 

This has the same features as the scorch time in general. In compound design, choosing a curing system from this angle is very important since properties required are to be optimized. 

The plateau time is the indication of sensitivity to overcure which is particularly relevant to thick articles. This varies widely with different classes of accelerators. 

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