Captax 2-Mercaptobenzothiazole 149-30-4 R. T. Vanderbilt Catalysts / Accelerators / Vulcanizing agents >> Mercapto compounds >> Mercaptobenzothiazole (Thiazole) Rubber - Elastomer (Chloroprene, Butyl …) Natural rubber (NR) CAPTAX ® 2-Mercaptobenzothiazole Primary accelerator for NR and synthetic rubbers. Non-staining and non-discoloring. 2-Mercaptobenzothiazole. Used as a non-staining and a non-discoloring primary accelerator for NR and synthetic rubbers.