After digging around (mostly fruitlessly), I think I may have found the chemical I saw in an very old Rema MSDS on their patches. Z
inc diethyldithiocarbamate is similar to what I recall from that old MSDS. It is a primary accelerator and it is classified as an ultra-fast accelerator according to this article. The z
inc diethyldithiocarbamate is a primary accelerator while the n-ethylcyclohexylamine is used as a secondary accelerator to promote the primary. The two part system makes for stable storage. The presence of the secondary accelerator in the fluid can lead to polymerization of rubber in the fluid (there is some, of course) but it is slow which results in the shorter shelf life.