Pre-vulcanisation inhibitor

OB, OB A Optical brightener, optical brightening agent PVI Pre-vulcanisation inhibitor... 

Addition of sulfur in isolation, or with other chemicals, e.g., teft-butyl-2-benzothiazole sulfenamide and a pre-vulcanisation inhibitor. 

Other additives such as a pre-vulcanisation inhibitor and a sulphur-based cure system with accelerators were also present but at low levels, I.e. <1-2%. 

The first delayed action accelerators were introduced in 1925 with the development of 2-mercaptobenzothiazole (MET) and 2-mercaptobenzothiazole disulfide (or 2,2"-dithiobisbenzothiazole) (MBTS) (a.5-a.7). Even more delayed action and yet faster-curing vulcanisation became possible in 1937 with the introduction of the first commercial benzothiazolesulfenamide accelerator (a.8, a.9). Further progress was made in 1968 with the introduction (a. 10) of pre-vulcanisation inhibitor (PVI), A-cyclohexylthiophthalimide (CTP), which can be used in small concentrations together with benzothiazole sulfenamide accelerators. The history of the progress toward faster vulcanisation with better control of premature vulcanisation or scorch is illustrated by Figure 2. 

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