Sulfurless Crosslinking of Diene Rubbers with 2-R-4,6-Dithiol-S-Triazines

Abstract

Abstract A novel crosslinking formulation comprising a combination of 2-dibutyl-amino-4,6-dithiol-s-triazine (DB) with a radical agent gave a crosslinked polybutadiene in which 2-dibutylamino-s-triazine-4,6-dithio crosslinks were formed. The recommended radical agents are dibenzothiazyl disulfide, 1-(o-nitrophenylazo)-p-cresol, benzeneazo-α-naphthylamine, dicumyl peroxide, and 2,5-dimethyl-2,5-di-t-butylperoxyhexane. The crosslinking efficiency and aging resistance of the resulting vulcanizates were much improved compared to vulcanizates with a similar formulation without DB. The BR crosslinking formulation using 2-R-4,6-dithiol-s-triazines, where R was an antioxidant substituent, gave vulcanizates with aging resistant properties remaining after solvent extraction. Similar crosslinking effects were also confirmed on diene rubbers to yield vulcanizates with improved aging resistance. Typical formulations and the properties of the resulting vulcanizates are given for SBR, IR, NBR, NR, and EPDM.