Accelerator MBTS (DM) in Rubber Vulcanization
Accelerator MBTS (DM, CAS 120-78-5) is a thiazole-type accelerator used to control the sulfur vulcanization of rubber. This page explains what it does, where it is used, and how it differs from MBT and the sulfenamides.
What it does in the cure system
| Role | What happens |
|---|---|
| Accelerator | The benzothiazole fragment speeds crosslinking of the rubber with sulfur |
| Sulfur donation | The disulfide (-S-S-) group can participate in crosslinking |
| Secondary accelerator | Blends with DPG or a sulfenamide to tune the cure |
MBTS needs the zinc oxide/stearic acid activator system and elemental sulfur, and is often boosted with DPG or combined with a sulfenamide.
Where MBTS is used
| Product | Role of MBTS |
|---|---|
| Tyres | General or secondary accelerator |
| Technical goods | Belts, hoses, mouldings |
| Footwear and general rubber | Economical general-purpose acceleration |
MBTS vs MBT and the sulfenamides
| Accelerator | Class | Scorch / speed | Notes |
|---|---|---|---|
| MBT (M) | Thiazole thiol | Faster, lower scorch safety | Higher bloom |
| MBTS (DM) | Thiazole disulfide | More controlled; better scorch than MBT | Lower bloom; amine-free |
| CZ / TBBS | Sulfenamide | Delayed | Longer scorch safety; tyres |
MBTS is the more controlled, cleaner-running member of the MBT/MBTS thiazole pair; it is chosen where a general-purpose, amine-free accelerator is wanted, and a sulfenamide is chosen where more delay is needed.
Why choose MBTS
- Versatile – works as a primary or secondary accelerator.
- Better scorch safety than MBT – a wider processing window.
- Less bloom than MBT – a cleaner compound surface.
- Amine-free – no amine-derived nitrosamine concern.
Frequently Asked Questions
Is MBTS the same as DM?
Yes – MBTS and DM are names for 2,2′-dibenzothiazyl disulfide (CAS 120-78-5).
How does MBTS differ from MBT?
MBT is the thiazole thiol; MBTS is its disulfide, generally with better scorch safety and less bloom.
Does MBTS need a co-accelerator?
It can be used alone, but is often boosted with DPG or combined with a sulfenamide to tune the cure.
Does MBTS contain an amine?
No – it is amine-free, so it does not carry the amine-derived nitrosamine concern of some accelerators.
Is MBTS a skin sensitiser?
Yes – like most accelerators it is a potential skin sensitiser; avoid skin contact.
Related reading
- Accelerator MBTS (DM, CAS 120-78-5): properties and applications
- Rubber antioxidants and accelerators: selection guide
- Accelerator CZ (CBS): properties and applications
- Accelerator MBTS (DM, CAS 120-78-5) – product page
PolyBlueChem supplies Accelerator MBTS (DM, CAS 120-78-5) for rubber vulcanization, with per-batch COA and SDS. Contact us with your application and tonnage.