Accelerators MBT, MBTS, CBS, TBBS and TMTD: How to Choose
A buyer's comparison of the common thiazole and sulphonamide accelerators, their cure speed and their scorch safety.
Accelerators control how fast the compound cures and how much processing safety it has before curing starts. Picking the wrong one is the fastest way to create scorch waste on a production line.
The common grades at a glance
- •MBT (M) — fast, economical, short scorch safety. Common in latex and in lightly loaded compounds.
- •MBTS (DM) — slightly slower than MBT with a little more processing safety; widely used in general mechanical goods.
- •CBS (CZ) — a delayed-action sulphonamide. Good balance of cure rate and scorch safety; a standard choice for tyre and belt compounds.
- •TBBS (NS) — similar to CBS with generally longer scorch safety and a fast cure once started. Widely used where thick sections need flow time before cure begins.
- •TMTD (TT) — a very fast thiuram; often used as a secondary accelerator or in low-sulphur / EV systems. Can bloom if overdosed.
What to ask for
Ask the supplier for the scorch time (t5 or ts2 at your mixer's test temperature) and the cure time (t90) together, not separately. A fast accelerator with no scorch data is a risk, not a saving. Also confirm whether the grade is supplied as powder, oil-treated powder or granules — dust control and weighing accuracy differ substantially between them. ## Need the documents or today's price? Send us the grade, quantity and destination port — we return a quotation with COA and MSDS attached. Email manager@fipolymer.com or use the inquiry form on this site.