Antioxidant RD (TMQ) in Tires and Rubber

Antioxidant RD (TMQ, CAS 26780-96-1) is an amine antioxidant used mainly in tyres and dark mechanical rubber goods, where it gives strong protection against heat, oxygen and flex-fatigue ageing. This page looks at how it is used in tyres and rubber, and how it fits alongside antiozonants.

Why RD in tires and rubber?

Property	Benefit
Amine chemistry	Strong protection against heat and fatigue ageing
Oligomeric (low volatility)	Stays in the compound through cure and long service
Granule form	Low dust, good dispersion in the mixer
Cost-effective	Strong protection at economical loadings

In tires

A tyre heats up as it runs and flexes constantly; its rubber must resist both heat ageing and fatigue ageing. RD is a core antioxidant for tyre compounds because it addresses both.

Part	Why RD helps
Tread	Heat build-up and fatigue at the running surface
Carcass / body	Long-term strength retention under heat and flex
Sidewall	Heat/oxygen protection (with an antiozonant)
Bead and innerliner	Durability under temperature cycling

In mechanical and dynamic rubber goods

Product	Why RD
Conveyor and transmission belting	Repeated flexing and heat build-up
Hoses	Heat and fatigue protection
Anti-vibration mounts	Dynamic fatigue resistance
General black rubber	Long-term heat/oxygen resistance

RD with antiozonants and cure systems

RD is almost always part of a protective package. In tyres it is typically used with a PPD antiozonant (6PPD or 7PPD):

Additive	Role
RD (TMQ)	Bulk heat and fatigue ageing protection
6PPD / 7PPD	Ozone cracking and dynamic surface fatigue
Secondary antioxidant (thioester)	Longer heat-ageing life
Sulfenamide accelerators	Cure system; cure rate confirmed by test

Because RD is a staining amine antioxidant, it is used in black and dark compounds; for light-coloured or white goods a non-staining phenolic antioxidant (2246, BHT) is used instead.

Frequently Asked Questions

What is Antioxidant RD used for in tyres?

It protects tyre compounds against heat and fatigue ageing, usually alongside a PPD antiozonant such as 6PPD.

Does RD discolour rubber?

Yes – it is a staining antioxidant, so it is used in black/dark goods, not white or light-coloured ones.

How does RD differ from 6PPD?

Both are amine antioxidants; RD is mainly a heat/fatigue antioxidant, while 6PPD is mainly an antiozonant/antiflex agent. Tyres often use both.

What level of RD is used?

A few phr, set with the antiozonant and cure system and confirmed by ageing tests.

Can RD be used in light-coloured goods?

No – use a non-staining phenolic antioxidant instead.