Extend scorch safety time

Inhibitors and retarders are sometimes used in the rubber curative package to extend scorch safety time for a rubber compound. 

CTP is used as a rubber compound additive to extend scorch safety time so that the rubber compound can be processed further in the factory without generating scrap. Also, CTP does not reduce the cured hardness or slow the cure rate as a conventional retarder would. The addition of CTP generates little or no change in the properties and performance of the cured compounded rubber. 

CTP as an inhibitor is rather unique. Conventional retarders will extend scorch safety time but also hurt the state of cure and the cure rate of the rubber compound. If rubber is processed at lower temperatures or subject to less heat history, it is possible to avoid scorch-related problems. However, this is not always feasible. Sometimes adjustments in the cure package, such as changes in the ratio of secondary to primary accelerator, can also lengthen the scorch safety time but possibly hurt cure rate. 

Usually MgO is used in neoprene or halobutyl rubber compounds as an acid acceptor and as a means of extending scorch safety time to reduce scrap in the factory. It also functions as a heat stabilizer in TPVs. 

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